The issue is with the Single band view.
Reproduction Sequence :
- Load Frequency, (by default the view is on Multi)
- Toggle to the Single band view,
-
Result : All the controls on top of the plugin window become empty, except for QC.
- Close the plugin window,
- Open the plugin Window,
-
Result : The controls on top of the window are back to normal.
When you are still in the Single view and have re-opened the window so the controls are back to normal, the following actions make the controls become empty again :
- Selecting another band, (either by clicking on its tab or by grabbing the band on the graph)
- Resetting the EQ, (ctrl/alt+click on Reset)
- Toggling back to the Multi view.
Added to the issues list, number 28.