Viewer is not being chosen after the first selection

This issue occurs when using the File Viewer add-on.

Expected behavior: When viewing a file in the Source tab, if that file can be viewed in one of the viewers included in the add-on, the file viewer drop-down is displayed on the panel:

A user selects a viewer and views a file in that viewer.

The issue: We discovered that viewer selection stopped working properly. To choose some viewer, you need to select it twice. Nothing happens after the first selection. You can see it on the video here.
This issue appears to be on the Bitbucket side.

Could you please investigate and fix this issue?