We were having some slowness with OpenProj over remote display. In the area marked in black, scrolling was sluggish with certain types of charts.
So a bit of Google work and the issue was resolved. There is a java setting that seems to greatly increase performance to remote display. The setting is found in the run.conf file which is placed in $HOME/.openproj. Change the JAVA_OPTS line to disable pmoffscreen:
JAVA_OPTS="-Xms128m -Xmx768m -Dsun.java2d.pmoffscreen=false -Djava.util.prefs.userRoot=/home/drichard/.java/.userPrefs -Djava.util.prefs.systemRoot=/home/drichard/.openproj"