User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0 Build ID: 20180503143129 Steps to reproduce: 1. Open Firefox in KDE Plasma workspace. 2. Menu -> Customize. 3. Check "hide title bar" option. 4. Try to resize the window with cursor on border. Actual results: Cannot resize window with cursor dragging on border. Maximize and minimize buttons work. Expected results: Resizing window by dragging border should work.

I am having the same issue, Running Arch Linux, using KDE, just updated Firefox today. Just replying to confirm the bug.

Hello, I have reproduced this issue on Ubuntu 16.04 with KDE Plasma work-space theme installed on the 3 main versions of Firefox (Release v60.0.2, Beta - v61.0b12, Nightly - v62.0a1) This issue does not occur on the Cinnamon theme of the Ubuntu default theme.

Same here with Linux 4.14.40, Manjaro KDE 64bits; Firefox 60.0.2 (64-bit). Once the title bar is disabled in the customize page, you need to enable it again to be able to resize the window.

Same problem here. Using Firefox 64.0 on Kubuntu 18.10 (KDE Plasma). If I turn off the title bar (Customise -> uncheck Title Bar), I am unable to resize the Firefox window (the border is missing an the mouse pointer does not change to resize arrow).

have had this issue for a while now when i dont use the system title bar. not just this system setup, but im currently on: Operating System: KDE neon 5.14 KDE Plasma Version: 5.14.4 Qt Version: 5.11.2 KDE Frameworks Version: 5.53.0 Kernel Version: 4.15.0-43-generic OS Type: 64-bit