There should be a property "Apex Properties" with a field for button gradient. You can either either clear that field or add a CSS gradient of your choice.
On the post it it seems you have some inconsistencies with the icons causing the overflow. But to widen the post it depending on the layout chosen go to message layout message user block width.
I'd take a shot and say that some of the HTML is messed up, such as an overflow issue like Steve mentioned. Widening may help a little but the problem would still remain. I'd need to see the html(board is closed) to look for a fix