Here's a shortcut you may not know about:
While using the CloudApp Desktop app (Legacy version), you can hover over the item you'd like to see and push the space bar to get a larger preview, without having to go to the web to view your content.
If you use an application to do text completion (like TextExpander). This can disable the ability to activate previews with your space bar. Not to worry, you can fix this by opening the keyboard preferences and, under Shortcuts, select *Text boxes and lists only*