In Revit you can create and control your own keyboard shortcuts. If you use a (for e.g., the "Items in Room") command frequently, you can open this window with your own defined shortcut.
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1. Go to View > User interface > Keyboard Shortcuts
2. User interface
3. Keyboard Shortcuts.
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4. Search for the command that you want to create a shortcut for (for e.g., the "Items in room" command). Under
5. Beside "Press new keys" insert the shortcut you want to assign to the command and press
6. Select "Assign":
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7. Select “ok”