Suggest to change your typed variable to another existing variable that has one or two characters in different (upper or lower) case.

When a variable is not found, you get the message

For instance if SomeObject has attribute StartDate, then in the exlusive split when entering "$SomeObject/Startdate" Mendix will say "could not find attribute 'Startdate'. It would be nice if Mendix would help me out a bit more and suggest: '... but I do see an attribute 'StartDate', shall I use that one?'

"Yes Mendix, please do. Thank you."

Same goes for Action Values in 'Change Variable', for variable names, but also for function names.

Call me lazy, but improvements of this kind make it easier and more fun to build Apps.