Make the new comment input box sized consistently

Each ticket has it's own comment input box.  However, when I resize one of them (adjust the splitter up or down), the others do not also resize.  This is quite annoying.  When I resize the comment box, then all of the comment boxes should resize as well.  That would provide a consistent experience across the tickets.

(I have no idea what topic this gets filed under - you guys can manage that.  There's way too many of them)