Product: Adobe InDesign
Version: 20.5
Forum post: https://forums.creativeclouddeveloper.com/t/flyout-menu-with-mutli-panel-plugins/11436/2

When creating a multi-panel UXP plugin and attaching a flyout menu to one of the panels, the flyout menuappears on a different panel than the one to which it is defined.

Steps to Reproduce
1. Create a UXP plugin for InDesign with multiple panels.
2. In the plugin’s entrypoints.setup, define a flyout menu for one of the panels.
3. Load/activate the plugin so all panels are present.
4. Look to which panel the flyout-menu gets attached. It's probably not the one defined in the entrypoints.setup.

Expected Result
The flyout menu appears at the panel where it was defined (i.e. the menu is bound / attached to the correct panel).

Actual Result
The flyout menu instead attaches to a seemingly random panel, not necessarily the one in which it was defined. It may be possible that it's randomly placed at the correct panel, though in my cases it was always wrong. It's not always the last panel defined (in one case it was the third panel with a total of four, though the menu was attached to the first panel in the entrypoints.setup.

Additional Notes
• The issue appears specific to InDesign. According to the forum post, the same plugin works correctly in Photoshop: each panel gets its proper flyout menu. 
• Bug was affirmed by another user in the forum post

I was going to upload a test-plugin demonstrating the issue. But weirdly I can neither upload a zip file nor a ccx file, which is weird for the official place to report bugs. You can get the test file from the forum post though.