Debian Testing, KDE, Xorg, GTX1060. Win10 (with/without ANGLE) is fine. STR: Open the library, e.g. Downloads by Ctrl+Shift+Y. Maximize the window. Actual: The window is maximized but transparent/empty. Unmaximizing makes the window black inside. Both can be fixed by hovering elements. Expected: The content should adjust to the new window size. Context: With non-WR OpenGL this is even reproducible with "last good". So WebRender regressed to the state of OpenGL. mozregression --repo mozilla-inbound --launch 4f55976a9e9115c9f41075843bc48955684364d9 --pref layers.acceleration.force-enabled:true layers.gpu-process.force-enabled:true Screencast: mozregression --repo mozilla-inbound --launch 2cee53dd577363866c3cc6ed7baf679a9936abbf --pref gfx.webrender.all:true layers.gpu-process.force-enabled:true mozregression --good 2018-05-26 --bad 2018-10-26 --pref gfx.webrender.all:true layers.gpu-process.force-enabled:true > 12:43.28 INFO: Last good revision: 4f55976a9e9115c9f41075843bc48955684364d9 > 12:43.28 INFO: First bad revision: 2cee53dd577363866c3cc6ed7baf679a9936abbf > 12:43.28 INFO: Pushlog: > https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=4f55976a9e9115c9f41075843bc48955684364d9&tochange=2cee53dd577363866c3cc6ed7baf679a9936abbf 2018-10-10 > 2cee53dd5773 Jeff Muizelaar — Bug 1496670. Update layout/reftests/async-scrolling/reftest.list for #3173 > bc87d3ddef61 Sotaro Ikeda — Bug 1461239 - Use InvalidateRenderedFrame() when necessary r=nical > 335625773207 Jeff Muizelaar — Bug 1495902. Create a shared Shaders object for all windows to use. r=jrmuizel > 7801a4fb37db Jeff Muizelaar — Bug 1496670. Update webrender to 923ee495bd9b0fda8a4a94c5a6cf42e2f0548731

Not reproducible with Gnome on Debian Testing. Either bug 1502519 would fix both OpenGL and WR, or you force WebRender to (again?) do a repaint and wontfix the other bug?