There are known issues for the game on FireFox 64-bit that are still being looked into. If you are having issues and are using FireFox, I would suggest trying either Chrome or Safari if you have the option. I apologize for the inconvenience, and thank you for the feedback!
Error: Error #3780
at starling.rendering::Painter/configureBackBuffer()
at starling.core::Starling/updateViewPort()
at starling.core::Starling/initialize()
at starling.core::Starling/onContextCreated()
Just hold down shift and click on the building you want to sell, or click and drag for multiple(You can find this in the instructions for the game on this html page as well). Thanks for trying it out! :)
 "King Cubes TD"){kind=icon}
 "Humanity Idle"){kind=icon}
 "Click It! 2"){kind=icon}
 "Idle Awards 2"){kind=icon}
 "Bubble Tanks Tower Heroes"){kind=icon}
 "Infinity Pirates"){kind=icon}
 "Idle Ants"){kind=icon}
 "Steampunk Idle Spinner"){kind=icon}
 "None of Your Business"){kind=icon}
 "The Perfect Tower"){kind=icon}
 "Idle Roller"){kind=icon}
 "Rocket Valley Tycoon"){kind=icon}
I apologize, commented out a bit of code while testing something. Will be fixed shortly.