In the Citrix session, you sometimes experience a problem with black blocks, frames, or stripes.
Poor performance is often connected with the delayed or slow refreshing of the screen content.
In the IGEL Setup or the configuration dialog in the UMS, activate one of the following parameters or all of them under Sessions > Citrix XenDesktop/XenApp > HDX / ICA Global > Options:
- Use server redraw
- Allow backing store
- Deferred screen update mode
See also Options in the manual chapter for Citrix.