Hey.
I'm not sure about posting CSS tweaks in here, but I figured this'd be useful to many people. This should work on almost all themes, and will replace the arrow at the top right of the composer, eg this:

With a drag bar that can be used to resize the composer to any size, eg this:

This does not add any additional functionality to the composer- this ability already exists, this just makes it easier to use and more user-transparent that the option is available.
To use:
Just paste the below CSS at the bottom of your Custom CSS:
/*Custom Composer Bar Tweak by Arc*/ .composer .resizer .trigger i:before { content: "\f0c9"; cursor: n-resize; } .composer.maximized .resizer .trigger i:before { content: "\f0c9"; cursor: n-resize; } .composer .resizer { position: absolute; width: 100%; top: 10px; height: 0; cursor: n-resize; } .composer .resizer .trigger i { margin-left: -10%; position: relative; color: #FFF; font-size: 14px; } .composer .resizer .trigger { position: relative; display: block; width: 110%; height: 20px; top: -10px; margin: 0 auto; margin-left: -11px; background: rgba(0,0,0,0.1); border: 0px solid #E4E4E4; -webkit-border-radius: 50%; -moz-border-radius: 50%; -ms-border-radius: 50%; -o-border-radius: 50%; border-radius: 0%; line-height: 20px; -o-transition:.3s ease-in-out; -ms-transition:.3 ease-in-outs; -moz-transition:.3s ease-in-out; -webkit-transition:.3s ease-in-out; transition:.3s ease-in-out; } .composer .resizer .trigger:hover { background: rgba(0,0,0,0.2); -o-transition:.3s ease-in-out; -ms-transition:.3 ease-in-outs; -moz-transition:.3s ease-in-out; -webkit-transition:.3s ease-in-out; transition:.3s ease-in-out; }