When I scroll text file or a browser web page over Thinlinc the text flickers what makes it hard to read (follow the current reading position). To reproduce open a long text file and scroll down or open a web page with text in Firefox and scroll down.
Might be related to the TigerVNC bug? https://github.com/TigerVNC/tigervnc/issues/211
Since the upstream bug is closed now, it's probably sufficient to do a new vendor drop into ThinLinc.
This got merged in r31143 as part of bug 2251.