Hello,
Some system tray icons do not react when you try to use the application key to open up a menu. In such cases, you have to use your mouse with aid of your screen reader to do the job. Below you will find specific instructions for JAWS and NVDA.
JAWS: pressing 'JAWSKey+F11 will bring up a list that contains the items that reside on your system tray. Simply pick the Dropbox item from the list and press enter. JAWS should right-click on it for you.
NVDA: If you use NVDA, then the thing will be different. Locate the Dropbox tray icon using TAB and arrow keys. Make sure that the NumLock is off, and press INSERT+NumPad * to move the mouse pointer to the icon. Finally, press NumPad / to perform a right-click on it.
Hope this helps.
Standing by the window, eyes upon the moon,
Hoping that the memory will leave her spirit soon.