Unsupported elements are not shown in the toolbar

Steps to reproduce:

1. Add a package/ asset with a hack in the unity toolbar
2. Right click on the toolbar and select "Unsupported user elements"
3. The elements should be added in the toolbar

Actual results: the elements are either not showing or displayed in a weird/unusable way in the toolbar

Expected results: elements can still be shown and interactable in the toolbar

Tested on (OS): Windows, MacOS

Notes:

• The behavior is different regarding the different Unity versions, this should be homogenized and fixed in all of them