so I switched to mudlet 3 just now and have this one problem where, even while maximized, mudlet decides on startup (twice) to resize it back to a small portion of the actual available space. Peeking around didn't reveal anything to set this right and am very confused by mudlet's behavior here. Googling didn't reveal anything useful, so if anybody got a solution... please share.
my work around is right now to initialize all my gui functions _after_ mudlet stopped being confused and stays maximized, but that's annoying.
edit: seems to be even worse then I thought. tabbing in/out of the gui can distort gui settings (like your typing bar being overshadowed) and you have a chance on the size of the type bar changing to multiline that it will also result down to small. yay.