I just got my OP-1 and I love it. However, I’m disabled and can only really use one hand to play. The OP-1 requires the shift key to be held down for a lot of functions, which needs two hands. Is there a way to lock the shift key and toggle it on and off, like caps lock? On iOS you can double tap shift to lock it, and I’m looking for something similar with this. Right now I’m using an object to hold the key down when I need it, but it’s not very elegant.
Elegant schmelegant. Was going to suggest a piece of tape, but a heavy object also works. 
As far as I knew, OP1 doesn’t have that lock function.
Maybe put a weight on it?
A clothespin or some type of chip clip might work.
This is a tricky one. Would have been totally awesome if TE had implemented this type of feature.
Depending on which hand you can use, you do kind of get into the habit of doing everything one handed after a while. I’m lucky in that I have quite wide hands, and I use my left hand to do most of the work.
Hope you can find an elegant solution or you manage to get used to it. TE are a pretty cool company, and considering the braille on the machine I would imagine that they are quite keen to ensure their machine can be used by anyone, so given your disability it might be worth dropping them an e-mail to see if they might consider an update (no harm in trying).
That would be really cool @domatron! Maybe something like hold shift + press blue encoder to enable shift lock then press blue encoder to undo shift lock.
As far as I knew, OP1 doesn't have that lock function.I think a small lead weight is your best bet here. (The idea is known for keyboards: http://kvgear.com/products/key-dog)
Maybe put a weight on it?