Fix sporadic crashes in various calls to [TWinControl].SetFocus, with the new class helper .TrySetFocus

source/apphelpers.pas

@@ -165,6 +165,11 @@ type
     property TryAsText: String read GetTryAsText write SetTryAsText;
   end;
 
+  TWinControlHelper = class helper for TWinControl
+  public
+    procedure TrySetFocus;
+  end;
+
   TAppSettingDataType = (adInt, adBool, adString);
   TAppSettingIndex = (asHiddenColumns, asFilter, asSort, asDisplayedColumnsSorted, asLastSessions,
     asLastActiveSession, asAutoReconnect, asRestoreLastUsedDB, asLastUsedDB, asTreeBackground, asIgnoreDatabasePattern, asLogFileDdl, asLogFileDml, asLogFilePath,
@@ -3570,6 +3575,18 @@ begin
 end;
 
 
+procedure TWinControlHelper.TrySetFocus;
+begin
+  try
+    if Enabled and CanFocus then
+      SetFocus;
+  except
+    on E:EInvalidOperation do
+      MessageBeep(MB_ICONWARNING);
+  end;
+end;
+
+
 { TAppSettings }
 
 constructor TAppSettings.Create;

source/main.pas

@@ -1634,7 +1634,7 @@ begin
         SelectNode(DataGrid, 0);
     end else begin
       ToggleFilterPanel(True);
-      SynMemoFilter.SetFocus;
+      SynMemoFilter.TrySetFocus;
     end;
   end else begin
     MessageBeep(MB_ICONASTERISK);
@@ -1647,7 +1647,7 @@ begin
   // Go to multi column filter generator
   if PageControlMain.ActivePage = tabData then begin
     ToggleFilterPanel(True);
-    editFilterSearch.SetFocus;
+    editFilterSearch.TrySetFocus;
   end else begin
     MessageBeep(MB_ICONASTERISK);
   end;
@@ -6072,7 +6072,7 @@ begin
 
     // Do not steel filter while writing filters
     if not SynMemoFilter.Focused then
-      vt.SetFocus;
+      vt.TrySetFocus;
 
     DataGridFocusedNodeIndex := Min(DataGridFocusedNodeIndex, Int64(vt.RootNodeCount)-1);
     SelectNode(vt, DataGridFocusedNodeIndex);
@@ -6252,13 +6252,14 @@ begin
   // Move focus to relevant controls in order for them to receive keyboard events.
   // Do this only if the user clicked the new tab. Not on automatic tab changes.
   if Sender = PageControlMain then begin
-    if tab = tabHost then PageControlHostChange(Sender)
-    else if tab = tabDatabase then ListTables.SetFocus
+    if tab = tabHost then
+      PageControlHostChange(Sender)
+    else if tab = tabDatabase then
+      ListTables.TrySetFocus
     else if tab = tabData then begin
-      if DataGrid.CanFocus and DataGrid.Enabled then
-        DataGrid.SetFocus;
+      DataGrid.TrySetFocus;
     end else if IsQueryTab(tab.PageIndex, True) then begin
-      QueryTabs.ActiveMemo.SetFocus;
+      QueryTabs.ActiveMemo.TrySetFocus;
       QueryTabs.ActiveMemo.WordWrap := actQueryWordWrap.Checked;
       SynMemoQueryStatusChange(QueryTabs.ActiveMemo, [scCaretX]);
     end;
@@ -6297,7 +6298,7 @@ begin
   else if tab = tabProcesslist then list := ListProcesses
   else if tab = tabCommandStats then list := ListCommandStats
   else Exit; // Silence compiler warning
-  list.SetFocus;
+  list.TrySetFocus;
   UpdateFilterPanel(Sender);
   PageControlTabHighlight(PageControlHost);
 end;
@@ -12138,7 +12139,7 @@ begin
   // Show new tab
   if Sender <> actNewQueryTabNofocus then begin
     SetMainTab(QueryTab.TabSheet);
-    QueryTab.Memo.SetFocus;
+    QueryTab.Memo.TrySetFocus;
   end;
 end;
 

source/table_editor.pas

@@ -2280,12 +2280,10 @@ begin
   listCheckConstraints.EndEditNode;
   // Ensure SynMemo's have focus, otherwise Select-All and Copy actions may fail
   if PageControlMain.ActivePage = tabCREATEcode then begin
-    if SynMemoCreateCode.CanFocus then
-      SynMemoCreateCode.SetFocus;
+    SynMemoCreateCode.TrySetFocus;
   end
   else if PageControlMain.ActivePage = tabALTERcode then begin
-    if SynMemoALTERcode.CanFocus then
-      SynMemoAlterCode.SetFocus;
+    SynMemoAlterCode.TrySetFocus;
   end;
   UpdateSQLcode;
   TExtForm.PageControlTabHighlight(PageControlMain);