I have two screens: one is connected to VGA, and the second is connected to HDMI. If I move window to center of VGA-0 screen it become invisible: the frame is not shown, but it appears on task bar.
Please provide output of qdbus org.kde.KWin /KWin supportInformation
KWin Support Information: The following information should be used when requesting support on e.g. http://forum.kde.org. It provides information about the currently running instance, which options are used, what OpenGL driver and which effects are running. Please post the information provided underneath this introductory text to a paste bin service like http://paste.kde.org instead of pasting into support threads. ========================== Version ======= KWin version: 5.10.5 Qt Version: 5.9.1 Qt compile version: 5.9.1 XCB compile version: 1.11.1 Operation Mode: X11 only Build Options ============= KWIN_BUILD_DECORATIONS: yes KWIN_BUILD_TABBOX: yes KWIN_BUILD_ACTIVITIES: yes HAVE_INPUT: yes HAVE_DRM: yes HAVE_GBM: yes HAVE_X11_XCB: yes HAVE_EPOXY_GLX: yes HAVE_WAYLAND_EGL: yes X11 === Vendor: The X.Org Foundation Vendor Release: 11903000 Protocol Version/Revision: 11/0 SHAPE: yes; Version: 0x11 RANDR: yes; Version: 0x14 DAMAGE: yes; Version: 0x11 Composite: yes; Version: 0x4 RENDER: yes; Version: 0xb XFIXES: yes; Version: 0x50 SYNC: yes; Version: 0x31 GLX: yes; Version: 0x0 Decoration ========== Plugin: org.kde.breeze Theme: Blur: 0 onAllDesktopsAvailable: false alphaChannelSupported: true closeOnDoubleClickOnMenu: false decorationButtonsLeft: 0 decorationButtonsRight: 3, 4, 5 borderSize: 3 gridUnit: 10 font: Liberastika,10,-1,5,50,0,0,0,0,0,Regular smallSpacing: 2 largeSpacing: 10 Options ======= focusPolicy: 1 nextFocusPrefersMouse: false clickRaise: true autoRaise: false autoRaiseInterval: 750 delayFocusInterval: 300 shadeHover: false shadeHoverInterval: 250 separateScreenFocus: false placement: 4 focusPolicyIsReasonable: true borderSnapZone: 10 windowSnapZone: 10 centerSnapZone: 0 snapOnlyWhenOverlapping: false rollOverDesktops: true focusStealingPreventionLevel: 1 legacyFullscreenSupport: false operationTitlebarDblClick: 5000 operationMaxButtonLeftClick: 5000 operationMaxButtonMiddleClick: 5015 operationMaxButtonRightClick: 5014 commandActiveTitlebar1: 0 commandActiveTitlebar2: 30 commandActiveTitlebar3: 2 commandInactiveTitlebar1: 4 commandInactiveTitlebar2: 30 commandInactiveTitlebar3: 2 commandWindow1: 7 commandWindow2: 8 commandWindow3: 8 commandWindowWheel: 31 commandAll1: 10 commandAll2: 3 commandAll3: 14 keyCmdAllModKey: 16777251 showGeometryTip: false condensedTitle: false electricBorderMaximize: true electricBorderTiling: true electricBorderCornerRatio: 0.25 borderlessMaximizedWindows: false killPingTimeout: 5000 hideUtilityWindowsForInactive: true inactiveTabsSkipTaskbar: false autogroupSimilarWindows: false autogroupInForeground: true compositingMode: 1 useCompositing: true compositingInitialized: true hiddenPreviews: 1 glSmoothScale: 2 xrenderSmoothScale: false maxFpsInterval: 16666666 refreshRate: 0 vBlankTime: 6000000 glStrictBinding: true glStrictBindingFollowsDriver: true glCoreProfile: true glPreferBufferSwap: 101 glPlatformInterface: 1 windowsBlockCompositing: true Screen Edges ============ desktopSwitching: false desktopSwitchingMovingClients: false cursorPushBackDistance: 1x1 timeThreshold: 150 reActivateThreshold: 350 actionTopLeft: 0 actionTop: 0 actionTopRight: 0 actionRight: 0 actionBottomRight: 0 actionBottom: 0 actionBottomLeft: 0 actionLeft: 0 Screens ======= Multi-Head: no Active screen follows mouse: no Number of Screens: 2 Screen 0: --------- Name: HDMI-0 Geometry: 1440,0,1920x1080 Refresh Rate: 60 Screen 1: --------- Name: VGA-0 Geometry: 0,180,1440x900 Refresh Rate: 74.9844 Compositing =========== Compositing is active Compositing Type: OpenGL OpenGL vendor string: X.Org OpenGL renderer string: Gallium 0.4 on AMD ARUBA (DRM 2.49.0 / 4.10.0-33-generic, LLVM 4.0.0) OpenGL version string: 4.1 (Core Profile) Mesa 17.0.7 OpenGL platform interface: GLX OpenGL shading language version string: 4.10 Driver: Unknown GPU class: Unknown OpenGL version: 4.1 GLSL version: 4.10 Mesa version: 17.0.7 X server version: 1.19.3 Linux kernel version: 4.10 Direct rendering: Requires strict binding: yes GLSL shaders: yes Texture NPOT support: yes Virtual Machine: no OpenGL 2 Shaders are used Painting blocks for vertical retrace: no Loaded Effects: --------------- zoom slidingpopups kwin4_effect_logout kwin4_effect_login slide kwin4_effect_windowaperture screenshot kwin4_effect_translucency minimizeanimation desktopgrid coverswitch colorpicker kwin4_effect_fade kwin4_effect_maximize kwin4_effect_frozenapp kwin4_effect_morphingpopups kwin4_effect_dialogparent presentwindows highlightwindow blur contrast startupfeedback screenedge kscreen Currently Active Effects: ------------------------- blur contrast Effect Settings: ---------------- zoom: zoomFactor: 1.2 mousePointer: 0 mouseTracking: 0 enableFocusTracking: false followFocus: true focusDelay: 350 moveFactor: 20 targetZoom: 1 slidingpopups: fadeInTime: 150 fadeOutTime: 250 kwin4_effect_logout: kwin4_effect_login: slide: kwin4_effect_windowaperture: screenshot: kwin4_effect_translucency: minimizeanimation: desktopgrid: zoomDuration: 300 border: 10 desktopNameAlignment: 0 layoutMode: 0 customLayoutRows: 2 usePresentWindows: true coverswitch: animationDuration: 200 animateSwitch: true animateStart: true animateStop: true reflection: true windowTitle: true zPosition: 900 primaryTabBox: false secondaryTabBox: false colorpicker: kwin4_effect_fade: kwin4_effect_maximize: kwin4_effect_frozenapp: kwin4_effect_morphingpopups: kwin4_effect_dialogparent: presentwindows: layoutMode: 0 showCaptions: true showIcons: true doNotCloseWindows: false ignoreMinimized: false accuracy: 20 fillGaps: true fadeDuration: 150 showPanel: false leftButtonWindow: 1 rightButtonWindow: 2 middleButtonWindow: 0 leftButtonDesktop: 2 middleButtonDesktop: 0 rightButtonDesktop: 0 highlightwindow: blur: blurRadius: 12 cacheTexture: true contrast: startupfeedback: type: 1 screenedge: kscreen:
Do you have a panel between the screens?
Created attachment 107908 [details] Screenshot with panel "between" screens. I'm not sure, because it seems to me that it is on HDMI-0 screen.
Fixed in 5.11 *** This bug has been marked as a duplicate of bug 371199 ***