Small update: I got in contact with jdk-updates-dev because I thought it
was fixed in older versions but it was just reverted.
The original issue which seems to have caused the bug was
https://bugs.openjdk.org/browse/JDK-8185862
Then, this was reverted specifically for 17 and 21 in
https://bugs.openjdk.org/browse/JDK-8348625
But the same issue still remains in 23+
The target issue that I was pointed to:
https://bugs.openjdk.org/browse/JDK-8336862. This is medium prio (P3),
but was unassigned recently. Some of the linked issues mention RDP, but
some are about VM or headless. But they all seem to be related to each
other.
My personal findings regarding RDP specifically:
1. This bug only occurs when two physical Windows machines are involved.
Connecting with a virtual machine or from Linux to Windows do not seem
to have this issue. Windows seems to choose software rendering in these
cases.
2. No JVM flags that disable hardware acceleration or similar seem to
work, and neither does disabling hardware acceleration in Windows
Settings or the group policy editor for RDP connections.
3. Just minimizing the java application window does **not** work as a
workaround either.
4. The only actual workaround I've found is installing a virtual display
driver and then forcing RDP to use that display
(https://github.com/VirtualDrivers/Virtual-Display-Driver
<https://urldefense.com/v3/__https://github.com/VirtualDrivers/Virtual-Display-Driver__;!!ACWV5N9M2RV99hQ!O4jMVhbDZHM1cbGpKNHhtFIvGx0WfkSoFLCL45a4tr9abzFRDOQvsJONP9lf_CoE8PWp-KmPUZ9UKJx3LXh7mg$>)
But that workaround is too much of a hassle to propose for our users.
--
Edward
