Typing into edit box of GUI Matlab app with virtual numpad is impossible

Hi, I have installed my compiled application to a tablet with Windows 8.1 32bit. I need to type numbers into edit boxes very often, so I would like to use virtual numpad only (no letters) to save space on display. I can type with the internal Windows virtual keybord (alphanumeric - with letters), but I cannot do it with any of the third party software (numpads). GUI window is always inactive somehow. On a notebook, it works without problem. Any thouths? Thanks in advance, Filip