Some programs have floating panels within the main window. Since the ability to focus them with keyboard only depends on the framework they are using, is there a way to use AutoHotKey to do this instead?
For example, PDF-XChange Viewer has a bookmark panel. The panel has to be focused if I want to insert a bookmark with Ins, or selecting bookmarks with keyboard arrows. If not, the Ins key simply has no use, or the arrow keys move the current pages.
The yellow in the title bar indicate that the panel is focused:
The panel isn't focused yet. Only clicking in the red box can focus it. Clicking on other locations (title bar, buttons, scrolling handle, moving it around) doesn't make it focused at all: