Shrinking a preview window in the web UI can stall when the cursor enters its iframe, preventing resizing of the window to be smaller. Windows can still be resized by moving the mouse outside of the window (e.g. for shrinking vertically, mouse would need to be to the right/left of the window), but this is clunky.
Problem seems to be that the resize library listens for mouse events in the parent window, but iframe events don't reach it (iframe input is already disabled for dragging and panning, but not resizing).
I have a working fix locally that I can PR when I get a chance.
This doesn't happen for every window type, but it definitely affects the markdown preview windows