Firstly, great tool and well done, I was happy to pay the small amount to support a good project.
My suggestions are
Tactile switch should bridge centre rail.
Make potentiometer footprint smaller as to allow easier jumper wire connections.
Make tuning potentiometer easier, can be difficult to know if it's turning.
15v+ to 15v- available from supply.
LDR and a way of shading it.
If I select voltage or current views (on right-side pannel) and then I click hand icon to interact with the project, it resets to standard, would flow better if voltage is selected then it should stay on voltage until I chose to click back to standard.
Autosave feature would be great, I've lost work to crashes.
Despite the list, i think its still a great tool and will be happy to support in the future