Correctly select the active label row in the label set widget
Summary: Always select an active label. Only do this if the user selects the first column and not if the user clicks on the icons for visibility etc.
Test Plan:
manual testing
- adding / removing labels
- adding / changing layers
- renaming labels
Reviewers: kislinsk, s434n, O1 MITK Reviewer Group I, floca
Reviewed By: O1 MITK Reviewer Group I, floca
Subscribers: floca
Maniphest Tasks: T29077
Differential Revision: https://phabricator.mitk.org/D625