Hey there, if you couldn't solve the issue you were having, elementaryOS keeps the .desktop entries under your home directory. All you need to do is use the solution provided before by geop0p3, but instead of Alacarte use the following steps.
EDIT: The following have been tested only on elementaryOS, if you try this solution on Ubuntu might just not work.
"You can add --disable-gpu to the launch command of the app."
Open the file
"appimagekit-gravit-designer.desktop" with your text editor. That file is located inside
Once you have that file open in your editor, you'll notice some properties are being defined there, you just need to change the Exec property to make it look like this:
Exec="/home/kenny/tmp/GravitDesigner.AppImage" %U --disable-gpu
Once you have edited the file, save the changes.
Logout. When you log back in, the application launcher will pick up your changes.
I use elementaryOS as well