What can happen is that the EnterEvent is received later than the TabletPressEvent, which causes KisInputManager to stop blocking one single mouse event. Steps to reproduce: 1. Move cursor to somewhere in Krita but outside the canvas 2. Without letting the stylus hover for long, slam (not literally) the stylus on the canvas area Possible solution: Some of the logic handled for QEvent::Enter in KisInputManager::eventFilterImpl should happen in both QEvent::Enter and QEvent::TabletPress, but only executed in either one, whichever is earlier, until QEvent::Leave has happened. 00000025 5.67603922 [11208] krita.tabletlog: vvvvvvvvvvvvvvvvvvvvvvv START TABLET EVENT LOG vvvvvvvvvvvvvvvvvvvvvvv 00000026 5.79502439 [11208] krita.tabletlog: "[ ] KeyRelease key: 0x1000000 mod: 0x0 text: \u001B" 00000027 6.37379503 [11208] krita.tabletlog: "[ ] TabletEnterProximity" 00000028 6.37434769 [11208] krita.tabletlog: Start blocking mouse events 00000029 6.37601137 [11208] krita.tabletlog: "[ ] TabletMove btn: 0 btns: 0 pos: 401, 109 gpos: 452, 244 hires: 451.682, 244.429 prs: 0.000000 Stylus Pen id: 131183 xTilt: 0 yTilt: 0 rot: 0 z: 0 tp: 0 " 00000030 6.39284706 [11208] krita.tabletlog: "[ ] TabletMove btn: 0 btns: 0 pos: 398, 111 gpos: 449, 246 hires: 448.839, 246.061 prs: 0.000000 Stylus Pen id: 131183 xTilt: 0 yTilt: 0 rot: 0 z: 0 tp: 0 " 00000031 6.39429712 [11208] krita.tabletlog: "[ ] TabletPress btn: 1 btns: 1 pos: 398, 111 gpos: 449, 246 hires: 448.839, 246.061 prs: 0.174805 Stylus Pen id: 131183 xTilt: 60 yTilt: -15 rot: 0 z: 0 tp: 0 " 00000032 6.39661694 [11208] krita.tabletlog: "[ ] TabletMove btn: 0 btns: 1 pos: 396, 111 gpos: 447, 246 hires: 447.259, 246.219 prs: 0.174805 Stylus Pen id: 131183 xTilt: 60 yTilt: -12 rot: 0 z: 0 tp: 0 " 00000033 6.39917707 [11208] krita.tabletlog: "[ ] TabletMove btn: 0 btns: 1 pos: 394, 112 gpos: 445, 247 hires: 445.258, 246.693 prs: 0.174805 Stylus Pen id: 131183 xTilt: 60 yTilt: -8 rot: 0 z: 0 tp: 0 " 00000034 6.39939308 [11208] krita.tabletlog: "[ ] TabletMove btn: 0 btns: 1 pos: 392, 112 gpos: 443, 247 hires: 443.152, 247.483 prs: 0.174805 Stylus Pen id: 131183 xTilt: 60 yTilt: -3 rot: 0 z: 0 tp: 0 " 00000035 6.39991379 [11208] krita.tabletlog: "[ ] TabletMove btn: 0 btns: 1 pos: 390, 114 gpos: 441, 249 hires: 441.151, 248.588 prs: 0.176758 Stylus Pen id: 131183 xTilt: 59 yTilt: 0 rot: 0 z: 0 tp: 0 " 00000036 6.40008926 [11208] krita.tabletlog: "[ ] TabletMove btn: 0 btns: 1 pos: 388, 115 gpos: 439, 250 hires: 439.413, 249.747 prs: 0.176758 Stylus Pen id: 131183 xTilt: 59 yTilt: 4 rot: 0 z: 0 tp: 0 " 00000037 6.40037251 [11208] krita.tabletlog: "[ ] Enter " 00000038 6.40041828 [11208] krita.tabletlog: Stop blocking mouse events 00000039 6.40061760 [11208] krita.tabletlog: "[ ] MouseMove btn: 0 btns: 0 pos: 398, 112 gpos: 449, 246 hires: 449, 246 Source:0" 00000040 6.41110849 [11208] krita.tabletlog: "[ ] TabletMove btn: 0 btns: 1 pos: 387, 116 gpos: 438, 251 hires: 437.728, 251.011 prs: 0.179688 Stylus Pen id: 131183 xTilt: 59 yTilt: 6 rot: 0 z: 0 tp: 0 " 00000041 6.41167498 [11208] krita.tabletlog: Start blocking mouse events 00000042 6.41423845 [11208] krita.tabletlog: "[ ] TabletMove btn: 0 btns: 1 pos: 385, 118 gpos: 436, 253 hires: 436.412, 252.643 prs: 0.182617 Stylus Pen id: 131183 xTilt: 59 yTilt: 9 rot: 0 z: 0 tp: 0 "
Git commit 1eb8b965f9eafd84e5e1a42189be3e21af4381a0 by Alvin Wong. Committed on 05/03/2018 at 15:11. Pushed by alvinwong into branch 'master'. Don't allow mouse events if pen is pressed M +9 -3 libs/ui/input/kis_input_manager.cpp M +1 -1 libs/ui/input/kis_input_manager_p.h https://commits.kde.org/krita/1eb8b965f9eafd84e5e1a42189be3e21af4381a0
Git commit 0ff9ff767f619976d3a323869b04df4f2caa99b1 by Alvin Wong. Committed on 05/03/2018 at 15:13. Pushed by alvinwong into branch 'krita/4.0'. Don't allow mouse events if pen is pressed (cherry picked from commit 1eb8b965f9eafd84e5e1a42189be3e21af4381a0) M +9 -3 libs/ui/input/kis_input_manager.cpp M +1 -1 libs/ui/input/kis_input_manager_p.h https://commits.kde.org/krita/0ff9ff767f619976d3a323869b04df4f2caa99b1