Resizing on Mac OS X

Whenever I try to resize the Minecraft window, it bugs out. It isn't resizing properly, and it goes "out of the frame". See pictures. I doesn't matter if I use a Resource Pack or not. Sometimes it resizes almost perfect, but everything is blurry.

When I run Minecraft in fullscreen, it resizes properly, but I can't because I have dual monitors. When I run Minecraft in fullscreen with dual monitors, the secondary screen gets black. I don't know if that's a bug also.