Bug 2146: Keyboard preferences: mouse can select wrong item

Steps to reproduce:
1. Open preferences
2. Select the keyboard category
3. Scroll down the list by any amount
4. Select an item using the mouse. The list scrolls to the top and the wrong item is selected.

The problem occurs because if the list of shortcuts is currently not the focus, then after a left mouse click, KeyView::OnSetFocus() is called, and setting the selection in that function interferes with the mouse selection.

Fix: In KeyView::OnSetFocus(), if there has been a left down event, don't select anything.

src/widgets/KeyView.cpp

@@ -1346,8 +1346,13 @@ KeyView::OnSetFocus(wxFocusEvent & event)
    {
       if (mLines.size() > 0)
       {
-         // if no selection, select first line, if there is one
-         SelectNode(LineToIndex(0));
+         // If mThereHasBeenALeftDown is true, then there is mouse
+         // selection in progress, so don't select anything here
+         // as this interferes with the mouse selection. (Bug 2146)
+         if (!mThereHasBeenALeftDown) {
+            // if no selection, select first line
+            SelectNode(LineToIndex(0));
+         }
       }
       else
       {
@@ -1373,6 +1378,8 @@ KeyView::OnKillFocus(wxFocusEvent & event)
    {
 	   RefreshRow(GetSelection());
    }
+
+   mThereHasBeenALeftDown = false;
 }
 
 //
@@ -1618,6 +1625,8 @@ KeyView::OnKeyDown(wxKeyEvent & event)
 void
 KeyView::OnLeftDown(wxMouseEvent & event)
 {
+   mThereHasBeenALeftDown = true;
+
    // Only check if for tree view
    if (mViewType != ViewByTree)
    {

src/widgets/KeyView.h

@@ -164,6 +164,8 @@ private:
    int mCommandWidth;
    wxCoord mKeyWidth;
 
+   bool mThereHasBeenALeftDown{};
+
 #if wxUSE_ACCESSIBILITY
    KeyViewAx *mAx;
 #endif