#815 Mouse-wheel scrolling issue

[- Wanderer -]

When a tight-vnc windowed-client session has a larger resolution than the host screen, a vertical scoll-bar appears in the window. If you scroll the window using the mouse wheel, the client looses the focus. This does not happen if you scroll the window by using the scroll-bar. Clicking inside the window has no effect (the client does not re-gain the focus), instead you must click in another window or the desktop and then click in the tight-vnc window in order to regain control of the client.