BYOND Version:513.1525
Operating System:Windows 10 Pro 64-bit
Web Browser:Chrome 81.0.4044.138
Applies to:Dream Seeker
Status: Resolved

This issue has been resolved.
Descriptive Problem Summary:

Windows with the "is pane" option enabled will show the corner dragger that resizable windows have even if they can't be resized.

Maybe related to this, the status bar stays on the window if you enable is-pane, so you have to disable it as a window and then re-enable is pane.
I'm looking into this but I can't seem to find any evidence this is even possible outside of the editor. All of the code is telling me the resize grip is never visible in a pane in-game, but could appear in the editor due to the way it handles panes. Is there a test case that shows this happening that I can investigate?
Lummox JR resolved issue
Issue was apparently from an older beta and never confirmed in 513.1525.