Right clicking the "Show x more tabs" button wrongly brings up the context menu for the tab underneath

[SoftVision-CiprianMuresan]

[Affected versions]:

• Firefox 52.0.2 and above
• Tab Center 1.32.0 (release version)
• Tab Center custom repo build

[Affected Platforms]:

• All Windows

[Prerequisites]:

• Tab Center was already installed on a new profile.
• At least 4 tabs are opened.

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites.
2. Write a keyword that is not contained in any of the tab titles.
3. Right click on the "Show 4 more tabs" button.

[Expected result]:

• Search filter is cleared and all tabs are shown.

[Actual result]:

• The context menu for the tab underneath the "Show 4 more tabs" appears while the search filter is cleared.

[Notes]:

• Middle clicking in the "Show x more tabs" button clears the search filter just like a normal click. We should do the same for the right click because the context menu that appears can be confusing.
• All options from the context menu are actionable.
• The issue is not reproducible on Mac OS.
• See attached screen recording of the issue: