It can be annoying how the GIMP image editor’s image and toolbox windows are separate, if all of them are hidden behind another window you have to bring not only the image to the front but also the toolboxes. This could work much more productively, why not show all the toolboxes whenever a image is in the foreground?
GIMP has a preference that will do just that. In the main GIMP window, click File->Preferences. In the preferences dialog, select Window Management from the list. Under the heading Window Manager Hints, change the two drop down boxes to Utility window.