This does not however, automatically switch to the Dropbox folder while in the middle of a application dialog box; it simply opens up the Dropbox folder in the event you need to look into or open something within the Dropbox folder. To access the Dropbox folder from an application dialog box, you can drag the Dropbox folder into the "Favorites" section of the application save/open dialog box to access it within one click.
Ok, if you're still interested in a hot-key anyway to access the dropbox folder,
here's how to do it:
1. Open Automator: [Cmd]-[Spacebar], type in Automator.
2. Select Service, click Choose
3. Modify Service receives selected [text] in [any application] to Service receives [no input] in [any application].
4. Select the action Run Shell Script under Utilities, drag it over to the right pane.
5. Change the cat command to open ~/Dropbox . If your Dropbox folder is located somewhere else, please modify the pah accordingly.
6. Save as Open Dropbox Folder within Automator.
7. Open System Preferences: [Cmd]-[Spacebar], type in System Preferences .
8. Navigate to Keyboard -> Shortcuts
9. Scroll down to General
10. Ensure the checkbox for Open Dropbox Folder is checked (enabled).
11. Choose the Keystroke combination to open the Dropbox folder.
NOTE: If you choose [Option]-[Cmd]-[D], you may need to disable Turn Dock Hiding On/Off in the Launchpad & Dock section.
Enjoy!
