If I set an screen edge to window switcher (or alternate) there is no way to select a window, and keyboard events are not handled. For example: If I set to alternate window switcher with Cover flow, for example, no keyboard keys work, I can only use the mouse scroll or click on edges to change window, but there is no way to dismiss the switcher and select a window, other than moving the mouse to the screen edge again. QML switchers (such as the grid switcher) seem to react to mouse clicks on windows, but still there is no way to dismiss the switcher other than moving the mouse to the screen edge.
Created attachment 103547 [details] Screencast showing the bug in action The attached screencast shows the bug in action. In the meanwhile I tried pressing Esc, Enter, Space, ... (besides mouse clicks which are visible thanks to the mouse click effect). It also shows the bug https://bugs.kde.org/show_bug.cgi?id=375321 in action: it is hard to trigger the window switcher moving the mouse to the screen edge, as it might be immediately dismissed.
This got implemented as part of the touch screen edge support in Plasma 5.10