They are linked for the case of a "floating" SpeedBar, ie a standalone window containing only a speedbar so the user can place the speedbar wherever on the screen that she wants.Seeing as the topic you link to is reporting a general helphint problem where an inactive window doesn't produce help bubbles, I fail to see how these issues are linked.
It is reasonable use WA_ToolBar for that window, so that the focus can't get "stuck" inside it, but also reasonable to want popup hints for the buttons in the SpeedBar.
You wouldn't want just any inactive window to produce help bubbles, but if you are working with a standalone toolbar and multiple project windows, you'd like the help bubbles
from the SpeedBar if any one of the project windows was active.
I guess one solution is to make it easy for the user to change the SpeedBar from Images to Images+Text in the case that he has forgotten what one of the images means.