"xvkbd" is a virtual keyboard application for X11. Clicking into it does not activate the window, because the clicked characters should be typed into the currently active window. KWin seems to get informed of this, because it does never draw the decorations for this window active.

When the Left click policy is set to "Activate & Raise", windows only get passed the click when they are active. Some

This feature, however, should be automatically deactivated for windows that do never go active, such as the "xvkbd" window mentioned above. Clicks into this window never get passed to the application. At least the second click should be passed (i.e. after the window got raised), otherwise "xvkbd" is unusable with that click policy.