Autodesk Revit offers an undocumented automatic palette hiding feature. You can set the project tree browser, properties, rebars, shared views, MEP fabrication, and other system palettes (non-modal dialogs) which offer by default only their docked or floating mode, so that they auto-hide.
If you're not working with them, they will wait dutifully in their minimized form as buttons at the edge of the screen, and they will expand to full size as soon as you hover over them (without clicking).
This is an undocumented and unsupported functionality, but it may be useful enough that you might want to turn it on permanently.
See the behavior of the modified palettes:
This automatic hiding of selected palettes can be enabled by editing the configuration file RevitUILayout.xml in the folder %appdata%\Autodesk\Revit\Autodesk Revit 20XX\ (depending on your Revit version). If this file is missing, you have probably not yet customized the position or appearance of your palettes. This file is updated when you exit Revit.
So exit Revit and open this text file in Notepad or in Notepad++. Locate the parameter CanAutoHide inside the XML definition your requested palettes and change its value from False to True. Save the file.
After you restart Revit, your palettes will be hidden (minimized) when idle, resp. they will display a pin with "Auto Hide", which can be used to activate and deactivate the auto-hide mode.
(author of the tip: Kevin Fielding)