At last I've got around to documenting this really useful feature. I programme the # key to toggle the display of all work features.
Run up Inventor, go to TOOLS/CUSTOMIZE and select the KEYBOARD tab. Find "All Work Features" from the "command name" list and add the key "#" as shown below. click on OK, and you can now toggle the Work Features display with one keystroke!!
This is broken in 2013!
However follow these notes carefully in order to get it to work in 2013.
Navigate to the path below and edit InventorCustomization.xml file using Notepad.
Use the Find command in Notepad to locate "AppiMateGlyphVisibilityCmd"
Copy & paste the line below "AppiMateGlyphVisibilityCmd" keyboard shortcut.
Edit the second occurence as "AppAllWorkfeaturesCmd"=hex:06,00,00,00,01,00,de,00,0f,c8