9c8eb0bcb9
This was happening because the strip modifier types register their panels when the editor is created, but the poll functions of these panels did not check for the view type. To fix this, add a condition to the `modifier_ui_poll` that checks if the view type is not `SEQ_VIEW_PREVIEW` when the panel is added to a sequencer space. Pull Request: https://projects.blender.org/blender/blender/pulls/145964