when some software was installed, there may be a desktop created automatically. However, there may be some strange that the desktop location of the software located in the un-wanted catagories and it's expected to change the catagories.
the following steps may help change the desktop icon catagories:
1--find the place that the dekstop icon in the Applications, and it located in the left top corner of the window by default, all the related desktop icons locate in /usr/share/applications:
2--find the desktop icon definition file manually by checking or the file names, a.desktop/b.desktop ...... or by grep operation with the following command:
'grep [keywords] ./ -r '
3--edit the content of a.desktop by changing the Categories. if you don't know how to set this parameter, you can check the settings of already existed icons in this catagory. And in addition, it's OK to check the defintions of this parameter by official definition with this link:Desktop檔案Categories詳細說明_BlueShaw的專欄-CSDN部落格 .