Some labs have the VMs setup to automatically change the resolution to match the size of the lab window. If you set the VM’s resolution yourself in one of these labs, it will not stay at that resolution. You can override this automatic setting to ensure your setting stays in place, however, once the Auto-adjust screen resolutions field is unchecked, its functionality cannot be turned back on even if you recheck the box. You will need to manually adjust the VM's screen resolution.
To ensure the VM’s resolution retains your setting, click the Support tab on the right side of the lab interface. Uncheck the Auto-adjust screen resolutions field. Now right-click the desktop of the VM you want to change, and set the resolution to the desired setting using the VM's operating system.
NOTE: This can cause problems with dialog boxes and other windows which may have a larger resolution than you set and could cause some items to be off screen or cause scroll bars to appear.