Large list or participants should be scrollable

A large list of participants will extend the content of the "Edit Event" window beyond the threshold of the window, making all checkboxes (Notify attendees, etc.) and part of the list inaccessible. This will also affect the Description and Attachments tabs. With a lot of moving and resizing, the window can be resized to show everything, but then it extends far beyond the size of the screen. This is impractical. The list of participants should never exceed the confines of the window and should be scrollable. 140.12.0esr (64-bit) on Ubuntu 24.04.