Displaymassage of right click popup is overlapped by OK button

well, at least there is no glitch / text overlap. :)
I agree it's annoying, but how do you propose we solve this? maybe add ellipsis at the end of the text and show a tooltip when hovering it?

Adds a tooltip to the dialog. Haven't added a "..." because I think it's unnecessary...

surely you can factor it out abit? :)

can you check the tooltip's handle is actually destroyed? (ie, no GUI handle leak?)

Moved the code...

Re destroying: Doesn't the Close function take care of that? That's what the comment in Tooltip.h says;

 /** Create the ToolTip control.
 @note Be careful about tooltip destruction! Unlike other widgets, tooltips aren't regular
 children; they are instead "owned" by their parent (Windows terminology). Therefore, unless the
 owner doesn't have any non-owner parent, Windows won't destroy the tooltip control when the
 owner is destroyed; so make sure you explicitly destroy it by calling the "close" method. */

Fixed in DC++ 0.860.