Thanks for posting here! All DisplayLink (the chipset inside the Plugable UGA-2K-A) based USB Graphics Adapters will work well only in Aero mode.
When you change the theme on Windows 7 to a non- Aero theme, the system goes into Basic mode and Aero is disabled.
Aero is not just providing a fancy look, it provides a cleaner, more powerful, more efficient way of rendering graphics. If Aero is disabled on Windows Vista/Windows 7, the OS automatically disables the Desktop Window Manager which many of the latest display drivers (including DisplayLink drivers) depend on to render graphics.
When Aero is disabled and you run the Windows Aero Troubleshooter, it will report that it had found Desktop Window ManagerDesktop Window Manager disabled.
In Basic mode when the Desktop Window Manager is disabled, you could see screen freezes, extreme latency and even blank screens.
The DisplayLink Drivers that are installed for the Plugable UGA-2K-A to work depends on the Desktop Window Manager for rendering Graphics on the connected monitor. So you do need to have Aero enabled for the Plugable UGA-2K-A to work without issues. Sorry about that!
Hope the above information helps in understanding why changing the theme and disabling Aero causes issues. If you need any additional information feel free to post back here or shoot us an email at firstname.lastname@example.org. We are here to help!