Just create a new project and right click on the project explorer area, click 7 times, sometimes one click already crashes. The problem always occurs with the right mouse button. Windows10, FX6100.
I tested versions 4.11, 4.14, 4.15, .4.16, 4.17, 4.18.
LoginId:f079faad4de325c66f9d38976b49f404
EpicAccountId:eae1963bf3594937ae325f008d89d88f
Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\Build++UE4+Release-4.18+Compile\Sync\Engine\Source\Runtime\Core\Public\Containers/Array.h] [Line: 610] Array index out of bounds: 0 from an array of size 0
UE4Editor_Core!FDebug::AssertFailed() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:414]
UE4Editor_SlateCore!SWidget::ExecuteActiveTimers() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:1000]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:869]
UE4Editor_SlateCore!SOverlay::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\soverlay.cpp:97]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:31]
UE4Editor_SlateCore!SPanel::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:12]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:31]
UE4Editor_SlateCore!SPanel::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:12]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:31]
UE4Editor_SlateCore!SPanel::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:12]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!SOverlay::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\soverlay.cpp:97]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:31]
UE4Editor_SlateCore!SPanel::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:12]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!SCompoundWidget::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\scompoundwidget.cpp:35]
UE4Editor_Slate!SScrollBox::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\widgets\layout\sscrollbox.cpp:985]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!SCompoundWidget::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\scompoundwidget.cpp:35]
UE4Editor_Slate!SBorder::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\widgets\layout\sborder.cpp:85]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!SCompoundWidget::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\scompoundwidget.cpp:35]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:31]
UE4Editor_SlateCore!SPanel::OnPaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\spanel.cpp:12]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:899]
UE4Editor_SlateCore!FSlateWindowElementList::FDeferredPaint::ExecutePaint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\rendering\drawelements.cpp:830]
UE4Editor_SlateCore!FSlateWindowElementList::PaintDeferred() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\rendering\drawelements.cpp:855]
UE4Editor_SlateCore!SWidget::Paint() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slatecore\private\widgets\swidget.cpp:958]
UE4Editor_Slate!FSlateApplication::DrawWindowAndChildren() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:1233]
UE4Editor_Slate!FSlateApplication::DrawWindowAndChildren() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:1322]
UE4Editor_Slate!FSlateApplication::PrivateDrawWindows() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:1473]
UE4Editor_Slate!FSlateApplication::DrawWindows() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:1190]
UE4Editor_Slate!FSlateApplication::TickApplication() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:1777]
UE4Editor_Slate!FSlateApplication::Tick() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:1595]
UE4Editor!FEngineLoop::Tick() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3378]
UE4Editor!GuardedMain() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor!GuardedMainWrapper() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor!WinMain() [d:\build++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:253]
kernel32
ntdll