This is an archive of the old MediaWiki-based ImageJ wiki. The current website can be found at imagej.net.
Help on Menu Item
The convenient command Help › Help on Menu Item allows you to open pages on specific menu items:
Error creating thumbnail: Unable to save thumbnail to destination
The mouse cursor will change to an arrow with a question mark and the next menu item on which you click will not execute that command but open the page on this Wiki that corresponds to the selected command.