Created attachment 48318 [details] System settings in foreground, konsole window showing through transparent pixels. Version: unspecified (using KDE 4.4.4) OS: Linux kwin correctly draws decoration buttons, window title bar and border. Below the title bar sometimes there is a row of transparent pixels (see attachment). If the application behind the window changes, these can be seen through the transparent pixels. The transparent pixels become filled in with the title bar colour while the window is being moved. When the window loses focus (I'm using focus follows mouse), the transparent pixels appear again. I assume this is a kwin bug. I'm also thinking these pixels have no normal purpose, hence the window occupies a few more vertical pixels than it needs to. Reproducible: Sometimes Steps to Reproduce: Move focus away from a window. The previous window gets a row of transparent pixels. Curiously not all apps suffered the bug. Both konqueror and konversation windows showed the bug, but konsole didn't. If this is a kwin bug, I'd have expected all apps to show the same symptoms. Actual Results: See screenshot for example. Expected Results: No gap between window title and application window. Fedora 13 + updates. KDE 4.4.4 Intel 64 bit CPU. Intel graphics.
What window decoration are you using ?
I haven't changed themes or other such settings, therefore I presume I'm using Oxygen. However there are a number of places where these settings can be changed, e.g. widget style, colours, window decorations - all within the "Appearance" system settings group. I not familiar with all of these, but I can check explicit values if you need more info. Thanks.
window decoration can be changed in "system settings -> Appearance -> Windows" The button at the top should state the decoration you are using. You can change decoration from there. Can you tell if the same issue appears with other decorations ?
I changed window decorations to Plastik, hit Apply, new decorations got applied to existing windows, but bug was still present as before. Also tried Keramik, same results. Finally changed it back to Oxygen (so I can now answer your original question - I am using Oxygen), bug is present with that also. So I don't think the bug is part of the decoration. I'm thinking it's related to compositing. I went to System Settings, Desktop, Desktop Effects, then unchecked "Enable desktop effects". The issue stopped, which was expected as transparency requires compositing. The interesting thing was I then enabled the desktop effects, but the bug has not returned. I'll try logging out/in, rebooting etc. on Monday and see if the bug returns. Thanks.
My fair guess is graphics driver problem. The window is composited from several textures for decorations and window content. This is done in a way that there is no gap. And if we look closely on the screenshot we see that there is no gap in the decoration between top and left. Only between window content and top decoration. I think it is a clamp to edge problem and by restarting compositing you got a new OpenGL context without the problem.
I had noticed that the border was correct and that the gap was only beneath the title area. It's not shown in the screenshot, but the right hand side of the window was the same - border ok, but gap between title bar and application area. Since the problem recurred across reboots for over a week, I'll check when I'm back at the problematic computer (Lenovo T400, Intel GPU) to see if I can recreate it. At least I have a workaround now. This might not be a KDE bug, but perhaps I can feed this report to Intel driver folks. Thanks.
I haven't seen this happen for a long time, so I'm closing my bug report. I'm now using Fedora 15 with KDE 4.7.2 and Xorg driver and server: xorg-x11-drv-intel-2.15.0-5.fc15.x86_64 xorg-x11-server-Xorg-1.10.4-1.fc15.x86_64 Not sure which component caused the bug, but at least it's fixed now.