Are the opposite cases just blank or are they doing something as well?
Your code seems to be turning the same solenoid On and Off at the same time for Button 6.
If the solenoid is defined as a double solenoid, then you want to use Forward/Reverse, rather than On/Off.
Forward will be one position and Reverse the other.
Here's an example.
On activates the value, but off just stops it. Off doesn't reverse it.