Info panel for selected objects is not properly synced with selection

[hajicj]

To replicate:

• select something,
• use MaskEraser to modify it.

The object will now be deselected (because of the remove+add trick to force efficient redraw), but it will not be removed from the info panel.

Possible solutions

1) Make the info panel a proper ListView 2) Ensure info label removal on remove_cropobject