SUMMARY When moving the cursor on the window's border (not the edges) a vertical or horizontal cursor appears. When double clicking there, the corresponding window should be vertically or horizontally maximized. STEPS TO REPRODUCE 1. Move cursor on window border 2. Double click OBSERVED RESULT Nothing happens, except if the cursor is on the top edge, then we get full maximization (horizontally and vertically) EXPECTED RESULT Vertical maximization after double-clicking on the top and bottom edges Horizontal maximization after double-clicking the left and right edges SOFTWARE/OS VERSIONS Operating System: Debian GNU/Linux KDE Plasma Version: 5.17.5 KDE Frameworks Version: 5.70.0 Qt Version: 5.14.2 Kernel Version: 5.9.0-1-amd64 OS Type: 64-bit Processors: 4 × Intel® Core™ i5-6500 CPU @ 3.20GHz Memory: 11,6 GiB ADDITIONAL INFORMATION Internally there seem to be two implementation possibilities (at least for x11): A true vertical or horizontal maximization state or just increasing the window's size. I am not sure, what would be better. I think either implementation would improve things – it could be changed later if we see advantages of the other implementation. I think I have this feature in my mind for more than a decade. Since Windows started to support that feature also about one decade ago, I guess it's time to have it available in Plasma, too. :-)
I note that there are already vertically maximize and horizontally maximize actions available in System Settings, Window Management, Window Behavior, Titlebar Actions, which are mapped to different single clicks on the maximize button by default. So, we don't need to decide in this bug whether it should be a window resize or "true" maximize as you put it, just make these actions available to double-clicking on the frames. Having used this feature in Windows for years I agree it is very useful, and once you know about it, it is easier to remember and more logical than right-clicking or middle-clicking the maximise button (I can never remember which will do which action, and right-click/middle-click is hard on a trackpad). Plus, often when you are thinking about making a window larger in one direction you already have the mouse hovering over one side of the frame, so double-clicking the frame is easy at this point.
It does.
(In reply to David Edmundson from comment #2) > It does. What does? As far as I can tell, the described desired behaviour does not currently happen.
(In reply to David Edmundson from comment #2) > It does. Is this configurable or a Plasma 6 thing? Here on Plasma 5 and Wayland with my current configuration I do not get the window only vertically or horizontally maximized via double click on the edges. If you have this behavior, do you know how you achieved it?