Kasp ->to switch there are buttons to press rather than one button
you'd press <OK> menu button
then scroll down 4 (or up 3) to 'input selection' then press <OK>
up/down to the next input then lastly <OK> button to switch.
So thats about 7 or8 button presses on the monitor. Im probably making it sound more complicated than it is to do- and if you do that often you'd get used to it pretty quick i would think.
So basically in answer to your question yes : its fairly easy to do, but its not like there is a single button to switch inputs.
I tried it without anything connected to vga so i dont know if theres some kind of sensing circuit going on aswell. But Im not about to connect both up to my pc simultaneously Im afraid.