I found that text longer than the window window was still being printing in it's entirety, when it should be truncated, so I changed the caption display part :
[code[IF ddgui_vals.moveable% OR LEN(ddgui_vals.main.wtext$)[/code]
to :
VIEWPORT x+1, y-caption_height%-3, width-2, caption_height%+4
DDGui_PrintIntern(ddgui_vals.main.wtext$, 3,1, TRUE)
VIEWPORT 0,0,0,0