I solved this problem on my Thinkpad T420s running Arch, but it should work on Ubuntu just the same.
Get the name of the Trackpoint:
$ xinput list
The name of the Trackpoint is referred to as <device>, if it contains spaces, the name must be put into quotes. On my T420s the Trackpoint is called "TPP/2 IBM TrackPoint".
Get the name ...
This can happen when the StartupWMClass doesn't correspond to the WMClass of the application. See this question for details on how it works and how to find the WMClass. In my case, setting the correct StartupWMClass in the .desktop file fixes this issue.
related to :
Kile icon buggy in left (launcher) bar (ubuntu 18.04)
On ubuntu 18.04
open the file : org.kde.kile.desktop
at : /usr/share/applications
add this line at the end of file : StartupWMClass=kile
press ALT+F2, r
It works for me