Programs are able to switch keyboard layout without user input or permission. I need to prevent this behavior. I have disabled all keyboard shortcuts for changing languages or input methods. I have disabled option "Let me use a different input method for each app window". I have googled extensively but almost all results point to those two options. Other suggest removing other keyboard layouts (this is not an option, we use 3 layouts and change the manually).
Is there any other way to prevent programs from changing the keyboard layout without user input?
EDIT: The program in question is Siemens SIMATIC Manager's Help window. When I open help and system has German keyboard layout installed, it's automatically selected, even tho the help file is entirely written in english. This behaviour interferes with other programs as German keyboard layout is incompatible with US english or Polish programer's layouts.