• NI Linux RT uses the Xfce Desktop Environment (see here)

  • Xfce Manual

• Which NI Real-Time Targets Support Embedded UI?

  • Archived: Real-Time Controllers and Real-Time Operating System Compatibility

• Embedded User Interface Doesn't Look Like Host User Interface

• My cRIO Not Shows the Screen When Disconnect It and Reconnected

Sometimes the fonts are not correct installed on the target system. To fix this, open a terminal, login as admin (remote per SSH or locally) and execute the following command. After a restart of the controller the fonts should look properly.

>> find /usr/share/fonts/X11 -type d -print0 | xargs -0 mkfontdir

See also: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P7i1SAC