Intellij IDEA launching another icon at start

Solution 1:

What happened

intellij-idea-community installs a perfectly working .desktop file: /usr/share/applications/intellij-idea-community.desktop. Sometimes however, a freshly installed application needs a log out/in to show up in Dash.

This is apparently the case in your situation. I tried installing it with the same result. Simply log out/in did the job:

Your home-made launcher does start up the application, but does not connect to the window, so a generic icon shows up to represent the window.

How to fix

Remove your own made launcher from /usr/share/applications/intellij_idea.desktop, log out and back in.

important note

In any way, since you tried lock the (incorrect?) icon to the launcher, make sure to remove any Intellij IDEA - related .desktop file from ~/.local/share/applications, since possibly remaining .desktop files will overrule the global one.