Can't switch input method in Sandbox in Windows 10/8

I’m a Chinese user of COMODO, I’m using Windows 10, Windows 8.1 Simplified Chinese version now,
and I’m using COMODO Firewall with the latest version(currently
But I found the problem since Windows 8 came out.

When I run an application in COMODO Sandbox, I can’t switch input methon in this application
neither press Ctrl+Shift nor click the input method icon in the tray directly will work.
In Windows 8, such problem seems related to “Fast Startup”
If I startup the computer after shut off it, the problem come out.
But if I reboot the computer and use Sandbox then, I can use input method normally.

However, in Windows 10, I can’t use input method in Sandbox at all, no matter how many times I restart my computer, or even disable Fast Startup in Control Panel, the input method won’t come out.

Is there any way to solve the problem?