1366766 - Dropdown menu from the Menu Bar buttons is not dismissed after fastly changing from one button to another

Status: NEW

(Firefox :: Menus, defect)

Description

[Emil Ghitta, QA [:emilghitta]]

Attachment: Menu Bar.gif

[Affected versions]:
Firefox 52.1.2(Build Id:20170517122419)
Firefox 53.0.3 (Build Id:20170518000419)
Firefox 54.0b9 (Build Id:20170518105722)
Firefox 55.0a1 (Build Id:20170522030207)

[Affected platforms]:
Windows (all).

[Steps to reproduce]:
1.Launch Firefox.
2.Open the Menu Bar.
3.Left-Click on a button.
4.Press the keyboard’s left or right arrow key and immediately Left-Click on another button.
5.Observe that the button’s drop down menu overlap each other.

[Expected result]:
The button’s drop down menu is dismissed after selecting another button.

[Actual result]:
The button’s drop down menu is not dismissed and if another button is selected the drop down menu's overlap each other.

[Regression range]:
This seems not to be a regression since this issue is reproducible on  older builds.

[Additional information]:
This issue is not reproducible on Mac and Linux Oses.
Please observe the attached video for more information about this issue.