tooltips are not selectable if there's just one tool and not a dropdown list
in CAS and spradsheet tools are not arranged in dropdown lists but stand on there own on the toolbar. For such tools in GG6 the tooltip appears when clicking on the tool but disappears if you don't hold the mouse clicked. You can't keep the tool selected, so you have to move the your mouse while still holding it clicked to select the question mark right of the tooltip. If not the tooltip disappears. When a tool is placed in a dropdown list, the tooltip remains after selecting a tool. I guess that's the way it should be for all tools.