Hello, This is a newbie question about how pd works with tk on OSX: in the directory bin of pd, there is a file called pd.tk and I suppose the code inside is used when we use the menu bar in pd and for dealing with all the new windows etc... what is this language ? Actually when I open pd, the main window is somewhere in between the middle and the left of the screen, so I thought I could change its position on the screen to fit my needs. I think I found the line code : canvas .dummy -height 2p -width 9c I tried several time to add randomly some options like -xpos or xscreen but nothing worked.... Generally, tk is used for MAC no ? but what is its first purpose and how where can find info to how to modify its code ? finally what is tcl then ? Thanks.