Reply To: Panels expanding every time I open a document

I’m afraid your preferences are corrupt. To reset them follow these steps:

Close the program

Hold down the Command-Option-Shift-Ctrl keys (on Windows, hold down Control-Alt-Shift) while you start the program up again.

While the program starts up, keep the keys held down until the splash screen appears along with an alert offering to “Delete InDesign Preferences File?”. Release the keys and click Yes.

When you rebuild preferences, you lose any custom application defaults you might have made in the Preferences dialog box, and any Presets you created (custom PDF presets, Document presets, etc.).

For more info, see this post https://creativepro.com/rebuilding-indesign-preferences.php