- Support nested task levels to allow tasks to overlap

 - Thread history loading, thus using the nested task elvels and fixing history interaction in recent builds
 - Thread initial database loads
 - Improve progress indicator slightly

10 files changed, 205 insertions, 62 deletions

diff --git a/Source/CustomQuery.m b/Source/CustomQuery.m
index 93567aa5..55c87129 100644
--- a/Source/CustomQuery.m
+++ b/Source/CustomQuery.m
@@ -364,7 +364,13 @@
 	if (customQueryCallbackMethod)
 		encodedCallbackMethod = [NSValue valueWithBytes:&customQueryCallbackMethod objCType:@encode(SEL)];
 	NSDictionary *taskArguments = [NSDictionary dictionaryWithObjectsAndKeys:queries, @"queries", encodedCallbackMethod, @"callback", nil];
-	[NSThread detachNewThreadSelector:@selector(performQueriesTask:) toTarget:self withObject:taskArguments];
+	
+	// If a helper thread is already running, execute inline - otherwise detach a new thread for the queries
+	if ([NSThread isMainThread]) {
+		[NSThread detachNewThreadSelector:@selector(performQueriesTask:) toTarget:self withObject:taskArguments];
+	} else {
+		[self performQueriesTask:taskArguments];
+	}
 }
 
 - (void)performQueriesTask:(NSDictionary *)taskArguments
@@ -745,7 +751,7 @@
 	// Set up the callback if present
 	if ([taskArguments objectForKey:@"callback"]) {
 		[[taskArguments objectForKey:@"callback"] getValue:&callbackMethod];
-		[self performSelectorOnMainThread:callbackMethod withObject:nil waitUntilDone:NO];
+		[self performSelectorOnMainThread:callbackMethod withObject:nil waitUntilDone:YES];
 	}
 
 	[tableDocumentInstance endTask];
diff --git a/Source/SPHistoryController.h b/Source/SPHistoryController.h
index 80aa08f2..56303807 100644
--- a/Source/SPHistoryController.h
+++ b/Source/SPHistoryController.h
@@ -24,7 +24,7 @@
 
 #import <Cocoa/Cocoa.h>
 
-@class TableDocument, TableContent;
+@class TableDocument, TableContent, TablesList;
 
 enum sphistory_view_types
 {
@@ -41,6 +41,7 @@ enum sphistory_view_types
 	IBOutlet NSSegmentedControl *historyControl;
 
 	TableContent *tableContentInstance;
+	TablesList *tablesListInstance;
 	NSMutableArray *history;
 	NSUInteger historyPosition;
 	BOOL modifyingHistoryState;
@@ -62,6 +63,7 @@ enum sphistory_view_types
 
 // Loading history entries
 - (void) loadEntryAtPosition:(unsigned int)position;
+- (void) loadEntryTaskWithPosition:(NSNumber *)positionNumber;
 - (void) abortEntryLoad;
 - (void) loadEntryFromMenuItem:(id)theMenuItem;
 
diff --git a/Source/SPHistoryController.m b/Source/SPHistoryController.m
index 7f522b7d..6c2683d0 100644
--- a/Source/SPHistoryController.m
+++ b/Source/SPHistoryController.m
@@ -51,6 +51,7 @@
 - (void) awakeFromNib
 {
 	tableContentInstance = [theDocument valueForKey:@"tableContentInstance"];
+	tablesListInstance = [theDocument valueForKey:@"tablesListInstance"];
 }
 
 - (void) dealloc
@@ -252,6 +253,7 @@
 
 /**
  * Load a history entry and attempt to return the interface to that state.
+ * Performs the load in a task which is threaded as necessary.
  */
 - (void) loadEntryAtPosition:(unsigned int)position
 {
@@ -262,6 +264,22 @@
 		return;
 	}
 
+	// Ensure a save of the current state - scroll position, selection - if we're at the last entry
+	if (historyPosition == [history count] - 1) [self updateHistoryEntries];
+
+	// Start the task and perform the load
+	[theDocument startTaskWithDescription:NSLocalizedString(@"Loading history entry...", @"Loading history entry task desc")];
+	if ([NSThread isMainThread]) {
+		[NSThread detachNewThreadSelector:@selector(loadEntryTaskWithPosition:) toTarget:self withObject:[NSNumber numberWithUnsignedInt:position]];
+	} else {
+		[self loadEntryTaskWithPosition:[NSNumber numberWithUnsignedInt:position]];
+	}
+}
+- (void) loadEntryTaskWithPosition:(NSNumber *)positionNumber
+{
+	NSAutoreleasePool *loadPool = [[NSAutoreleasePool alloc] init];
+	unsigned int position = [positionNumber unsignedIntValue];
+
 	modifyingHistoryState = YES;
 
 	// Update the position and extract the history entry
@@ -289,6 +307,10 @@
 	// Check and set the database
 	if (![[theDocument database] isEqualToString:[historyEntry objectForKey:@"database"]]) {
 		NSPopUpButton *chooseDatabaseButton = [theDocument valueForKey:@"chooseDatabaseButton"];
+		[tablesListInstance setTableListSelectability:YES];
+		[[tablesListInstance valueForKey:@"tablesListView"] deselectAll:self];		
+		[theDocument setDatabaseListIsSelectable:YES];
+		[tablesListInstance setTableListSelectability:YES];
 		[chooseDatabaseButton selectItemWithTitle:[historyEntry objectForKey:@"database"]];
 		[theDocument chooseDatabase:self];
 		if (![[theDocument database] isEqualToString:[historyEntry objectForKey:@"database"]]) {
@@ -298,7 +320,6 @@
 
 	// Check and set the table
 	if ([historyEntry objectForKey:@"table"] && ![[theDocument table] isEqualToString:[historyEntry objectForKey:@"table"]]) {
-		TablesList *tablesListInstance = [theDocument valueForKey:@"tablesListInstance"];
 		NSArray *tables = [tablesListInstance tables];
 		if ([tables indexOfObject:[historyEntry objectForKey:@"table"]] == NSNotFound) {
 			return [self abortEntryLoad];
@@ -308,10 +329,10 @@
 			return [self abortEntryLoad];
 		}
 	} else if (![historyEntry objectForKey:@"table"] && [theDocument table]) {
-		TablesList *tablesListInstance = [theDocument valueForKey:@"tablesListInstance"];
+		[tablesListInstance setTableListSelectability:YES];
 		[[tablesListInstance valueForKey:@"tablesListView"] deselectAll:self];		
 	} else {
-		[[theDocument valueForKey:@"tablesListInstance"] setContentRequiresReload:YES];	
+		[tablesListInstance setContentRequiresReload:YES];	
 	}
 
 	// Check and set the view
@@ -340,6 +361,10 @@
 
 	modifyingHistoryState = NO;
 	[self updateToolbarItem];
+
+	// End the task
+	[theDocument endTask];
+	[loadPool drain];
 }
 
 /**
diff --git a/Source/TableContent.h b/Source/TableContent.h
index 7126be5c..b93fa7f0 100644
--- a/Source/TableContent.h
+++ b/Source/TableContent.h
@@ -75,6 +75,7 @@
 	id contentFilterManager;
 
 	BOOL sortColumnToRestoreIsAsc;
+	BOOL tableRowsSelectable;
 	NSString *sortColumnToRestore;
 	unsigned int limitStartPositionToRestore;
 	NSIndexSet *selectionIndexToRestore;
@@ -90,7 +91,9 @@
 
 // Table interface actions
 - (IBAction) reloadTable:(id)sender;
+- (void) reloadTableTask;
 - (IBAction) filterTable:(id)sender;
+- (void)filterTableTask;
 - (IBAction) toggleFilterField:(id)sender;
 - (NSString *) usedQuery;
 - (void) setUsedQuery:(NSString *)query;
@@ -122,6 +125,7 @@
 - (void)updateNumberOfRows;
 - (int)fetchNumberOfRows;
 - (BOOL)saveRowOnDeselect;
+- (void)sortTableTaskWithColumn:(NSTableColumn *)tableColumn;
 
 // Retrieving and setting table state
 - (NSString *) sortColumnName;
diff --git a/Source/TableContent.m b/Source/TableContent.m
index 161dd316..da61414c 100644
--- a/Source/TableContent.m
+++ b/Source/TableContent.m
@@ -82,6 +82,7 @@
 		filterValueToRestore = nil;
 		firstBetweenValueToRestore = nil;
 		secondBetweenValueToRestore = nil;
+		tableRowsSelectable = YES;
 
 		isFiltered = NO;
 		isLimited = NO;
@@ -450,7 +451,10 @@
 
 	// Restore selection indexes if appropriate
 	if (selectionIndexToRestore) {
+		BOOL previousTableRowsSelectable = tableRowsSelectable;
+		tableRowsSelectable = YES;
 		[tableContentView selectRowIndexes:selectionIndexToRestore byExtendingSelection:NO];
+		tableRowsSelectable = previousTableRowsSelectable;
 	}
 	
 	// Update display if necessary
@@ -859,12 +863,17 @@
 
 /*
  * Reloads the current table data, performing a new SQL query. Now attempts to preserve sort
- * order, filters, and viewport. Performs the action in a new thread.
+ * order, filters, and viewport. Performs the action in a new thread if a task is not already
+ * running.
  */
 - (IBAction)reloadTable:(id)sender
 {
 	[tableDocumentInstance startTaskWithDescription:NSLocalizedString(@"Reloading data...", @"Reloading data task description")];
-	[NSThread detachNewThreadSelector:@selector(reloadTableTask) toTarget:self withObject:nil];
+	if ([NSThread isMainThread]) {
+		[NSThread detachNewThreadSelector:@selector(reloadTableTask) toTarget:self withObject:nil];
+	} else {
+		[self reloadTableTask];
+	}
 }
 - (void)reloadTableTask
 {
@@ -888,13 +897,17 @@
 
 /*
  * Filter the table with arguments given by the user.
- * Performs the action in a new thread.
+ * Performs the action in a new thread if necessary.
  */
 - (IBAction)filterTable:(id)sender
 {
 	if ([tableDocumentInstance isWorking]) return;
 	[tableDocumentInstance startTaskWithDescription:NSLocalizedString(@"Filtering table...", @"Filtering table task description")];
-	[NSThread detachNewThreadSelector:@selector(filterTableTask) toTarget:self withObject:nil];
+	if ([NSThread isMainThread]) {
+		[NSThread detachNewThreadSelector:@selector(filterTableTask) toTarget:self withObject:nil];
+	} else {
+		[self filterTableTask];
+	}
 }
 - (void)filterTableTask
 {
@@ -2488,7 +2501,7 @@
 /**
  * Sorts the tableView by the clicked column.
  * If clicked twice, order is altered to descending.
- * Performs the task in a new thread.
+ * Performs the task in a new thread if necessary.
  */
 - (void)tableView:(NSTableView*)tableView didClickTableColumn:(NSTableColumn *)tableColumn
 {
@@ -2501,7 +2514,11 @@
 
 	// Start the task
 	[tableDocumentInstance startTaskWithDescription:NSLocalizedString(@"Sorting table...", @"Sorting table task description")];
-	[NSThread detachNewThreadSelector:@selector(sortTableTaskWithColumn:) toTarget:self withObject:tableColumn];
+	if ([NSThread isMainThread]) {
+		[NSThread detachNewThreadSelector:@selector(sortTableTaskWithColumn:) toTarget:self withObject:tableColumn];
+	} else {
+		[self sortTableTaskWithColumn:tableColumn];
+	}
 }
 - (void)sortTableTaskWithColumn:(NSTableColumn *)tableColumn
 {
@@ -2554,15 +2571,18 @@
 	// If we are editing a row, attempt to save that row - if saving failed, reselect the edit row.
 	if (isEditingRow && [tableContentView selectedRow] != currentlyEditingRow && ![self saveRowOnDeselect]) return;
 	
-	// Update the row selection count
-    // and update the status of the delete/duplicate buttons
-	if ([tableContentView numberOfSelectedRows] > 0) {
-        [copyButton setEnabled:YES];
-        [removeButton setEnabled:YES];
-	} 
-	else {
-        [copyButton setEnabled:NO];
-        [removeButton setEnabled:NO];
+	if (![tableDocumentInstance isWorking]) {
+
+		// Update the row selection count
+		// and update the status of the delete/duplicate buttons
+		if ([tableContentView numberOfSelectedRows] > 0) {
+			[copyButton setEnabled:YES];
+			[removeButton setEnabled:YES];
+		} 
+		else {
+			[copyButton setEnabled:NO];
+			[removeButton setEnabled:NO];
+		}
 	}
 
 	[self updateCountText];
@@ -2717,7 +2737,7 @@
  */
 - (BOOL)tableView:(NSTableView *)aTableView shouldSelectRow:(NSInteger)rowIndex
 {
-	return ![tableDocumentInstance isWorking];
+	return tableRowsSelectable;
 }
 
 #pragma mark -
@@ -2756,6 +2776,7 @@
 	[copyButton setEnabled:NO];
 	[reloadButton setEnabled:NO];
 	[filterButton setEnabled:NO];
+	tableRowsSelectable = NO;
 }
 
 /**
@@ -2775,6 +2796,7 @@
 	}
 	[reloadButton setEnabled:YES];
 	[filterButton setEnabled:[fieldField isEnabled]];
+	tableRowsSelectable = YES;
 }
 
 #pragma mark -
diff --git a/Source/TableDocument.h b/Source/TableDocument.h
index f0e43fef..34df12f8 100644
--- a/Source/TableDocument.h
+++ b/Source/TableDocument.h
@@ -134,8 +134,9 @@ enum sp_current_query_mode
 	BOOL _encodingViaLatin1;
 	BOOL _shouldOpenConnectionAutomatically;
 	BOOL _isConnected;
-	BOOL _isWorking;
+	int _isWorkingLevel;
 	BOOL _mainNibLoaded;
+	BOOL databaseListIsSelectable;
 	int _queryMode;
 
 	BOOL taskDisplayIsIndeterminate;
@@ -175,6 +176,7 @@ enum sp_current_query_mode
 // Database methods
 - (IBAction)setDatabases:(id)sender;
 - (IBAction)chooseDatabase:(id)sender;
+- (void)chooseDatabaseTask;
 - (IBAction)addDatabase:(id)sender;
 - (IBAction)removeDatabase:(id)sender;
 - (IBAction)showMySQLHelp:(id)sender;
@@ -190,6 +192,7 @@ enum sp_current_query_mode
 - (void) setTaskProgressToIndeterminate;
 - (void) endTask;
 - (BOOL) isWorking;
+- (void) setDatabaseListIsSelectable:(BOOL)isSelectable;
 
 // Encoding methods
 - (void)setConnectionEncoding:(NSString *)mysqlEncoding reloadingViews:(BOOL)reloadViews;
diff --git a/Source/TableDocument.m b/Source/TableDocument.m
index 211c37c0..d17ee1e2 100644
--- a/Source/TableDocument.m
+++ b/Source/TableDocument.m
@@ -75,7 +75,8 @@
 		_mainNibLoaded = NO;
 		_encoding = [[NSString alloc] initWithString:@"utf8"];
 		_isConnected = NO;
-		_isWorking = NO;
+		_isWorkingLevel = 0;
+		databaseListIsSelectable = YES;
 		_queryMode = SP_QUERYMODE_INTERFACE;
 		chooseDatabaseButton = nil;
 		chooseDatabaseToolbarItem = nil;
@@ -902,8 +903,8 @@
 }
 
 /**
- * selects the database choosen by the user
- * errorsheet if connection failed
+ * Selects the database choosen by the user, using a child task if necessary,
+ * and displaying errors in an alert sheet on failure.
  */
 - (IBAction)chooseDatabase:(id)sender
 {
@@ -919,6 +920,21 @@
 		return;
 	}
 
+	// Lock editability again if performing a task
+	if (_isWorkingLevel) databaseListIsSelectable = NO;
+
+	// Start a task
+	[self startTaskWithDescription:[NSString stringWithFormat:NSLocalizedString(@"Loading database '%@'...", @"Loading database task string"), [chooseDatabaseButton titleOfSelectedItem]]];
+	if ([NSThread isMainThread]) {
+		[NSThread detachNewThreadSelector:@selector(chooseDatabaseTask) toTarget:self withObject:nil];
+	} else {
+		[self chooseDatabaseTask];
+	}
+}
+- (void)chooseDatabaseTask
+{
+	NSAutoreleasePool *taskPool = [[NSAutoreleasePool alloc] init];
+
 	// Save existing scroll position and details, and ensure no duplicate entries are created as table list changes
 	BOOL historyStateChanging = [spHistoryControllerInstance modifyingHistoryState];
 	if (!historyStateChanging) {
@@ -932,6 +948,8 @@
 			NSBeginAlertSheet(NSLocalizedString(@"Error", @"error"), NSLocalizedString(@"OK", @"OK button"), nil, nil, tableWindow, self, nil, nil, nil, [NSString stringWithFormat:NSLocalizedString(@"Unable to connect to database %@.\nBe sure that you have the necessary privileges.", @"message of panel when connection to db failed after selecting from popupbutton"), [chooseDatabaseButton titleOfSelectedItem]]);
 			[self setDatabases:self];
 		}
+		[self endTask];
+		[taskPool drain];
 		return;
 	}
 
@@ -956,6 +974,8 @@
 	else
 		[tableWindow makeFirstResponder:[tablesListInstance valueForKeyPath:@"tablesListView"]];
 
+	[self endTask];
+	[taskPool drain];
 }
 
 /**
@@ -1148,21 +1168,30 @@
 - (void) startTaskWithDescription:(NSString *)description
 {
 
-	// Set flags and prevent further UI interaction in this window
-	_isWorking = YES;
-	[historyControl setEnabled:NO];
-	[[NSNotificationCenter defaultCenter] postNotificationName:SPDocumentTaskStartNotification object:self];
+	// Increment the working level and set the task text
+	_isWorkingLevel++;
+	[taskDescriptionText setStringValue:description];
 
-	// Reset the progress indicator
-	taskDisplayIsIndeterminate = YES;
-	[taskProgressIndicator setIndeterminate:YES];
-	[taskProgressIndicator animate:self];
-	[taskProgressIndicator startAnimation:self];
-	taskDisplayLastValue = 0;
+	// Reset the progress indicator if necessary
+	if (_isWorkingLevel == 1 || !taskDisplayIsIndeterminate) {
+		taskDisplayIsIndeterminate = YES;
+		[taskProgressIndicator setIndeterminate:YES];
+		[taskProgressIndicator animate:self];
+		[taskProgressIndicator startAnimation:self];
+		taskDisplayLastValue = 0;
+	}
 
-	// Set the descriptive label and schedule appearance in the near future
-	[taskDescriptionText setStringValue:description];
-	taskDrawTimer = [[NSTimer scheduledTimerWithTimeInterval:0.2 target:self selector:@selector(showTaskProgressLayer:) userInfo:nil repeats:NO] retain];
+	// If the working level just moved to start a task, set up the interface
+	if (_isWorkingLevel == 1) {
+
+		// Set flags and prevent further UI interaction in this window
+		[historyControl setEnabled:NO];
+		databaseListIsSelectable = NO;
+		[[NSNotificationCenter defaultCenter] postNotificationName:SPDocumentTaskStartNotification object:self];
+
+		// Set the descriptive label and schedule appearance in the near future
+		taskDrawTimer = [[NSTimer scheduledTimerWithTimeInterval:0.2 target:self selector:@selector(showTaskProgressLayer:) userInfo:nil repeats:NO] retain];
+	}
 }
 
 /**
@@ -1189,6 +1218,11 @@
  */
 - (void) setTaskPercentage:(float)taskPercentage
 {
+	if (taskDisplayIsIndeterminate) {
+		taskDisplayIsIndeterminate = NO;
+		[taskProgressIndicator stopAnimation:self];
+	}
+
 	taskProgressValue = taskPercentage;
 	if (taskProgressValue > taskDisplayLastValue + taskProgressValueDisplayInterval
 		|| taskProgressValue < taskDisplayLastValue - taskProgressValueDisplayInterval)
@@ -1217,17 +1251,25 @@
 - (void) endTask
 {
 
-	// Cancel the draw timer if it exists
-	if (taskDrawTimer) [taskDrawTimer invalidate], [taskDrawTimer release], taskDrawTimer = nil;
+	// Decrement the working level
+	_isWorkingLevel--;
 
-	// Hide the task interface
-	if (taskDisplayIsIndeterminate) [taskProgressIndicator stopAnimation:self];
-	[taskProgressLayer setHidden:YES];
+	// If all tasks have ended, re-enable the interface
+	if (!_isWorkingLevel) {
+
+		// Cancel the draw timer if it exists
+		if (taskDrawTimer) [taskDrawTimer invalidate], [taskDrawTimer release], taskDrawTimer = nil;
 
-	// Re-enable window interface
-	_isWorking = NO;
-	[historyControl setEnabled:YES];
-	[[NSNotificationCenter defaultCenter] postNotificationName:SPDocumentTaskEndNotification object:self];
+		// Hide the task interface
+		if (taskDisplayIsIndeterminate) [taskProgressIndicator stopAnimation:self];
+		[taskProgressLayer setHidden:YES];
+
+		// Re-enable window interface
+		[historyControl setEnabled:YES];
+		databaseListIsSelectable = YES;
+		[[NSNotificationCenter defaultCenter] postNotificationName:SPDocumentTaskEndNotification object:self];
+		[mainToolbar validateVisibleItems];
+	}
 }
 
 /**
@@ -1236,7 +1278,15 @@
  */
 - (BOOL) isWorking
 {
-	return _isWorking;
+	return (_isWorkingLevel > 0);
+}
+
+/**
+ * Set whether the database list is selectable or not during the task process.
+ */
+- (void) setDatabaseListIsSelectable:(BOOL)isSelectable
+{
+	databaseListIsSelectable = isSelectable;
 }
 
 #pragma mark -
@@ -2700,7 +2750,12 @@
  */
 - (BOOL)validateMenuItem:(NSMenuItem *)menuItem
 {
-	if (!_isConnected || _isWorking) {
+
+	if ([menuItem menu] == chooseDatabaseButton) {
+		return (_isConnected && databaseListIsSelectable);
+	}
+
+	if (!_isConnected || _isWorkingLevel) {
 		return ([menuItem action] == @selector(newDocument:) || [menuItem action] == @selector(terminate:));
 	}
 
@@ -3205,7 +3260,7 @@
  */
 - (BOOL)validateToolbarItem:(NSToolbarItem *)toolbarItem;
 {
-	if (!_isConnected || _isWorking) return NO;
+	if (!_isConnected || _isWorkingLevel) return NO;
 
 	NSString *identifier = [toolbarItem itemIdentifier];
 
@@ -3302,7 +3357,7 @@
  */
 - (BOOL)windowShouldClose:(id)sender
 {
-	if (_isWorking) {
+	if (_isWorkingLevel) {
 		return NO;
 	} else if ( ![tablesListInstance selectionShouldChangeInTableView:nil] ) {
 		return NO;
diff --git a/Source/TablesList.h b/Source/TablesList.h
index e32ec789..3f29011c 100644
--- a/Source/TablesList.h
+++ b/Source/TablesList.h
@@ -104,6 +104,7 @@ enum sp_table_types
 	int selectedTableType;
 	NSString *selectedTableName;
 	BOOL isTableListFiltered;
+	BOOL tableListIsSelectable;
 	BOOL tableListContainsViews;
 
 	BOOL structureLoaded, contentLoaded, statusLoaded, alertSheetOpened;
@@ -146,6 +147,9 @@ enum sp_table_types
 - (void)setStatusRequiresReload:(BOOL)reload;
 - (BOOL)selectTableOrViewWithName:(NSString *)theName;
 
+// Tabview delegate methods
+- (void)loadTabTask:(NSTabViewItem *)tabViewItem;
+
 // Table list filter interaction
 - (void) showFilter;
 - (void) hideFilter;
@@ -155,5 +159,6 @@ enum sp_table_types
 // Task interaction
 - (void) startDocumentTaskForTab:(NSNotification *)aNotification;
 - (void) endDocumentTaskForTab:(NSNotification *)aNotification;
+- (void) setTableListSelectability:(BOOL)isSelectable;
 
 @end
diff --git a/Source/TablesList.m b/Source/TablesList.m
index 7bb5ae48..c5102121 100644
--- a/Source/TablesList.m
+++ b/Source/TablesList.m
@@ -697,9 +697,15 @@
 		return;
 	}
 
-	// Otherwise, set up a task and fire up a thread to deal with view changes and data loading
+	// Otherwise, set up a task
 	[tableDocumentInstance startTaskWithDescription:taskString];
-	[NSThread detachNewThreadSelector:@selector(updateSelectionTask) toTarget:self withObject:nil];
+
+	// If on the main thread, fire up a thread to deal with view changes and data loading, else perform inline
+	if ([NSThread isMainThread]) {
+		[NSThread detachNewThreadSelector:@selector(updateSelectionTask) toTarget:self withObject:nil];
+	} else {
+		[self updateSelectionTask];
+	}
 }
 
 - (void) updateSelectionTask
@@ -1294,8 +1300,8 @@
 - (BOOL)selectionShouldChangeInTableView:(NSTableView *)aTableView
 {
 
-	// Don't allow selection changes while performing a task
-	if ([tableDocumentInstance isWorking]) return NO;
+	// Don't allow selection changes while performing a task.
+	if (!tableListIsSelectable) return NO;
 
 	// End editing (otherwise problems when user hits reload button)
 	[tableWindow endEditingFor:nil];
@@ -1318,6 +1324,9 @@
 - (void)tableViewSelectionDidChange:(NSNotification *)aNotification
 {	
 
+	// Reset selectability after change if necessary
+	if ([tableDocumentInstance isWorking]) tableListIsSelectable = NO;
+
 	// Perform no action if the selected table hasn't actually changed - reselection etc
 	if ([tablesListView numberOfSelectedRows] == 1
 		&& [[filteredTables objectAtIndex:[tablesListView selectedRow]] length]
@@ -1405,12 +1414,16 @@
 
 /**
  * Loads structure or source if tab selected the first time,
- * using a threaded load.
+ * using a threaded load if currently on the main thread.
  */
 - (void)tabView:(NSTabView *)aTabView didSelectTabViewItem:(NSTabViewItem *)tabViewItem
 {
 	[tableDocumentInstance startTaskWithDescription:[NSString stringWithFormat:NSLocalizedString(@"Loading %@...", @"Loading table task string"), selectedTableName]];
-	[NSThread detachNewThreadSelector:@selector(loadTabTask:) toTarget:self withObject:tabViewItem];
+	if ([NSThread isMainThread]) {
+		[NSThread detachNewThreadSelector:@selector(loadTabTask:) toTarget:self withObject:tabViewItem];
+	} else {
+		[self loadTabTask:tabViewItem];
+	}
 }
 - (void)loadTabTask:(NSTabViewItem *)tabViewItem
 {
@@ -1595,6 +1608,7 @@
  */
 - (void) startDocumentTaskForTab:(NSNotification *)aNotification
 {
+	tableListIsSelectable = NO;
 	[toolbarAddButton setEnabled:NO];
 	[toolbarActionsButton setEnabled:NO];
 	[toolbarReloadButton setEnabled:NO];
@@ -1605,11 +1619,20 @@
  */
 - (void) endDocumentTaskForTab:(NSNotification *)aNotification
 {
+	tableListIsSelectable = YES;
 	[toolbarAddButton setEnabled:YES];
 	[toolbarActionsButton setEnabled:YES];
 	[toolbarReloadButton setEnabled:YES];
 }
 
+/**
+ * Set the table list to selectable or not during the task process.
+ */
+- (void) setTableListSelectability:(BOOL)isSelectable
+{
+	tableListIsSelectable = isSelectable;
+}
+
 #pragma mark -
 #pragma mark SplitView Delegate Methods
 
@@ -1636,6 +1659,7 @@
 		contentLoaded = NO;
 		statusLoaded = NO;
 		isTableListFiltered = NO;
+		tableListIsSelectable = YES;
 		tableListContainsViews = NO;
 		selectedTableType = SP_TABLETYPE_NONE;
 		selectedTableName = nil;
diff --git a/Source/YRKSpinningProgressIndicator.m b/Source/YRKSpinningProgressIndicator.m
index a1f70e9d..935d613c 100644
--- a/Source/YRKSpinningProgressIndicator.m
+++ b/Source/YRKSpinningProgressIndicator.m
@@ -287,10 +287,7 @@
 {
 	if (_isIndeterminate) _isIndeterminate = NO;
 	_currentValue = doubleValue;
-	if ([NSThread isMainThread])
-		[self displayIfNeeded];
-	else
-		[self performSelectorOnMainThread:@selector(displayIfNeeded) withObject:nil waitUntilDone:NO];
+	[self setNeedsDisplay:YES];
 }
 
 - (double)maxValue