this bug has been introduced in cb16fec6bb67cec15be3fc2aeb251ab524134073.
Line number: 70
Just comment it out and everything goes back to normal.
All these problems are related to the weird setting that you define space as group separator. When you e.g. enter the value "24 mm" where space is set as group separator then of course it's logical that the SW forbids you to enter "2,4 mm" because a decimal separator can never ever come in front of a group separator. Btw, Qt built-in widgets like QDoubleSpinBox show the same behaviour.A bit more info on the problem of erasing the first digit in constraint value edit box. It happens when I try to do something that will make the first character to become a space. It doesn't matter what exactly: backspace, erase selection, delete, or even putting a space at the beginning. Sometimes, it prevents entering spaces anywhere (isn't a problem, I don't type spaces into numbers). Sometimes, it prevents me from entering a comma. Comma and space seem to be interacting with each other somehow...