Can mouse middle button/scroll wheel button action like trackpad three fingers tap to look up dictionary easier

The only way I could get this to work is by creating a new service that looks up the word and than tells Dictionary.app to use the "all" filter.

1. Open /Applications/Automator.app and select the services template
2. in the top right part of the screen, you should see that the default input parameters Automator has selected ("Service receives selected text in any application") is just what you want
3. in the left hand search field, search for an Action called "Run Applescript" and drag it into your workflow

4. replace the part "(* Your script goes here *)" with the following Applescript, and than choose File->Save. Automator will ask you for a name for your new service (eg. "lookup in all dictionaries" and from that moment on, your service will be available in all applications.

   set dictLocation to "dict:///" & input
   open location dictLocation
    tell application "System Events" to tell process "Dictionary" to keystroke "0"    using command down
   

5. (optional) You might also want to define a shortcut for you new service by going into "System Preferences">"Keyboard">"Keyboard Shortcuts">"Services", finding your Service in the list of Services, and double-clicking the whitespace next to it do define a global shortcut.

This popover is built into the NSView class (showDefinitionForAttributedString:atPoint:). Since (as far as I can tell) it isn't controlled or powered by a distinct system process, it is completely owned by the app that owns the view where the popover was triggered.

In short, since the popover is owned solely by whatever app triggered it, there's no way to get rid of a stuck one without killing its parent app.

FYI, if the popover isn't dismissed with the escape key or by clicking outside of its body, something has gone wrong. I would file a bug report with the developers of the app where this happens.