chatview: fix issue with layout stacking

When the conversationview was resized horizontally to be small enough
so that only one pane is visible, the chatview header and footer would be visible, but clicking them would interact with the objects of
the pane below (the left side panel)

GitLab: #1868

Change-Id: Ic1fac91ef30fcc3078223e1705f10c8a112c2091