Default input language in Windows is English US. If you change to another language (in my case Greek) and then try to edit a cell on a dbgrid it automatically changes to default (English) either just by positioning the mouse on the cell or after exiting the grid. Same happens if Default is Greek, changing to English and then editing the Grid it changes back to Greek!
I tried to workaround by changing the keyboard at runtime with LoadKeyboardLayout(klId, KLF_ACTIVATE) but with same results.