Mac: Same tooltip shows after press expand button On the fixed tooltip in main editor

Steps:
1. Go-> preference->Debugger->General, check use "tooltips in main editor when debugging".
2. Start Debug a Qt Gui application or use the attachments.
3. Cursor Stay on arguments "*argv[ ] ",there will be a tooltip show.
4. Click stick button to fix the tooltip in this window.
5. Click expend-button in the first line.

Expected result:
The details of "*argv" will show in second line.

Actually result:.
According to attached screenshot,
when the "*argv" shows in second line .there will be another same tooltip show above it.