Go to the application in Finder, right-click it, and click “Show package contents”. Go inside the folder “Contents”, there you will find a file called info.plist, which is the file we are going to edit.
First make a backup in case you want to easily revert or if something goes wrong. If you have Xcode, open the file with Xcode, if not, open it with TextEdit. The reason I say TextEdit is because some plaintext editors cannot handle
Hover the mouse over any key and click the plus to create a new key. Name it
NSUIElement, and change the value to 1.
to the second last line, just before
Save the file, and restart the application. It will now run in the background.