Unable to resize windows

It sounds to me like you're using Gnome-classic with Compiz, and in that case resizing windows doesn't work because the plugin is disabled by default (not sure why).

To enable it, install CCSM:

sudo apt-get install compizconfig-settings-manager

Then run CCSM:

alt+f2ccsm+enter

Then in CCSM enable the resize plugin:
enter image description here

If resize doesn't work immediately, you may need to restart Compiz:

compiz --replace & disown