bug#81580: 30.2; frame resizing does not work under KDE Plasma / Wayland

> Date: Sat, 08 Aug 2026 17:29:15 +0200
> From: Bruno Haible via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <[email protected]>
> 
> Under the KDE Plasma window manager, it is normal to be able to
> resize a window by dragging one of its borders or one of its corners
> with the mouse. This has worked for me, for Emacs and most other
> programs, for the last 20 years, under X11. Under Wayland, however,
> this does not work for Emacs (it still works for most other programs):
> The first attempt to resize it changes the size only by a few pixels,
> and further attempts don't change it at all any more — or by several
> dozens of pixels, which feels like "random" behaviour.
> 
> Find attached a video of the interaction, on an Emacs instance
> opened through 'emacs -q'.
> 
> Platform details:
> Distro: Kubuntu 26.04
> Windowing system: Wayland
> KDE Plasma version: 6.6.5
> 
> This workaround from
> https://www.reddit.com/r/emacs/comments/1p0h08g/cant_resize_emacs_frame_by_dragging_frame_corners/
> works: adding this line to $HOME/.emacs:
> (setq frame-resize-pixelwise t)
> 
> But I claim that as a user, I should not need to do this workaround. In
> other words, Emacs should allow resizing its frame by default.
> Why?
> 1) Because that is what a normal user expects when most other programs
> allow resizing their windows in this way.
> 2) Because the documentation of this variable
> https://www.gnu.org/software/emacs/manual/html_node/elisp/Frame-Size.html#index-frame_002dresize_002dpixelwise
> suggests that it is only needed for making maximized/full-screen frames
> work. But here, the Maximize button works perfectly fine; it's the
> resizing with a mouse that does not work.

I think this is a known problem, caused by Wayland and GTK.  Our
recommendation is to use the PGTK build on Wayland.

Martin, any comments or suggestions?