Chrome OS version: 10428.0.0, 66.0.3352.0 dev channel eve device.

What steps will reproduce the problem?
(1) Open launcher to view All apps list and right click on any ARC++ app.
OR
(2) Open launcher and search for an app in the launcher search field.
Right click on this app in the search result.
(3) Context menu opens up.
(4) Click on uninstall option to view Uninstall app dialog box.

What is the expected result?
Launcher should remain open, it shouldn't slip down.

What happens instead?
Launcher slides down.

This is a regression bug as this is working fine on M65 build.
Please refer the videos attached for expected and actual behaviors.