I am using Thunderbird 128.3.1esr on Linux, using the KDE's Plasma 6 desktop environment with KWin using the Wayland protocol. I have installed two add-ons whose interface is blank: [https://addons.thunderbird.net/en-us/thunderbird/addon/tag-toolbar/ Tag Toolbar/Tag Popup] and [https://addons.thunderbird.net/en-us/thunderbird/addon/tagger/ Tagger]. Their interface opened when clicking on the button placed in the toolbar is blank. Namely, there is nothing to see but white space in the box that opened. For Tagger, it is possible to actually interact with the non-visible interface, but for Tag Toolbar this does not seem to be the case. I've attached a screenshot of Tagger's blank interface. * What could be the reason for this visual glitch? * Has anyone else encountered something similar before? * Is there more information I can gather to help resolve the issue?