Upgrade from 1.2 to 1.4 or 1.5 Scrolling content is overwriting itself

[Allen Chen]

Hi there,

After I upgraded guacamole from 1.2 to 1.5.3, scrolling content is 
overwriting itself in RDP session. I googled and found a similar issue 
https://www.reddit.com/r/archlinux/comments/ajac8i/scrolling_terminal_content_is_overwriting_itself/.

Server environments: CentOS 7.7, tomcat 8, jdk-13 and Apache proxy as 
the front end with SSL configured to redirect https to guacamole port 8080

Test 1: downgrade guacamole client to 1.3 and keep guacd on 1.5.3, 
scrolling content is working properly both via Apache proxy and direct 
access on port 8080;

Test 2: downgrade guacamole client to 1.4 and keep guacd on 1.5.3, 
scrolling content is not working properly via Apache proxy, but working 
properly via direct access on port 8080;

So the problem is on version 1.4 and 1.5.3 via Apache proxy.

To confirm this, I build a new machine with CentOS Stream release 8, 
tomcat 9 and jdk-20, I get exactly the same results listed in Test 1 and 
Test 2.

I took a screenshot:

Does anybody know what is the issue?

Thanks,

Allen