Basically, don't let the program you are running terminate!
That yellow line indicates that the command you called within gnome-terminal finished sucessfully. You can even hit "relaunch" to start the program (in this case, your command line twitter) again.
I would do the following: Since you are most likely interested in a continuous update of the twitter messages, run your program within the
watch command. This way, you can even define the interval "twitterTimeline.py" is run again!
Change your twitterText.desktop into the following:
Name=Text Twitter Timeline
Exec=/usr/bin/gnome-terminal --window-with-profile=Microblog --hide-menubar --command="watch -t -n 60 '/usr/bin/python /home/htplainf/twitterTimeline.py'"
Have a look at the Exec command in the last line:
watch -t -n 60 '/usr/bin/python /home/htplainf/twitterTimeline.py'
-n 60 means that your python script is executed every 60 seconds. You can easily set a different interval. Also, have a look at
man watch to discover its compete functionality!
By using watch, your command never stops, so you will not see the yellow message bar on top of gnome-terminal. And your tweets are updated!