Modal for editing content of Tree Menu panel not closed, when save button pressed

Description of problem:
Title says it all. This behavior is inconsistent with the behavior of other types of panel editors which are automatically closed, when their save button is pressed.

Version-Release number of selected component (if applicable):
BPMS 6.0.1 CR2

How reproducible:
Always

Steps to Reproduce:
1. login with root, navigate to Showcase workspace, Home page.
2. For menu 'Lateral Menu (Tree menu)' on the left side, click edit content
3. check some checkboxes and then click save button.

Actual results:
The modal for editting contents of Tree menu panel is not closed after save is clicked

Expected results:
To be consistent with behavior of other panel editors, the modal should be closed.