ChatControlBase: Rework drag and drop
This adds an overlay for both ChatControl and GroupChatControl. When dragging a file or contact over the control, an overlay with a drop hint is shown.
Fixes #9921 (closed)
This adds an overlay for both ChatControl and GroupChatControl. When dragging a file or contact over the control, an overlay with a drop hint is shown.
Fixes #9921 (closed)