My summary says by itself. I can unmaximize when I use touchpad or usb mouse. Neon dev unstable.
Can confirm. What I also noticed while playing with it: all the quick tiling regions don't work, either.
Fun thing to try: maximize a window, touch the decoration (but don't move) so that it goes into move resize mode, then use the arrow keys on your keyboard to move down -> window unmaximizes. The touch properly enters move resize, but we seem to not operate correctly on the updates.
Working on a patch, looks quite optimistic.
Patch at: https://phabricator.kde.org/D10431
Git commit 338c7362c9fbb37f1fb8beb9a50644b585d8135e by Martin Flöser. Committed on 21/02/2018 at 17:06. Pushed by graesslin into branch 'Plasma/5.12'. Properly handle move during touch events Summary: When a window was being moved the touch handling performed the wrong interaction. Due to that it was possible to move the window, but KWin did not enter the correct code paths, thus quick tiling was for example not functional. FIXED-IN: 5.12.3 Test Plan: New test case added and manual test in nested KWin Reviewers: #kwin, #plasma Subscribers: plasma-devel, kwin Tags: #plasma Differential Revision: https://phabricator.kde.org/D10431 M +69 -1 autotests/integration/quick_tiling_test.cpp M +15 -7 input.cpp https://commits.kde.org/kwin/338c7362c9fbb37f1fb8beb9a50644b585d8135e