Since I cant post in the Xojo forum I can start a thread here
Constants can have a type of Number (see below), String, Boolean, Color or Text.
Yes - when you define one in code you can define the specific type
The constant editor behaves more like you are using the style
Const foo = 10.0 Const bar = 10
with no specific type set
Being able to explicitly state the type was only added relatively recently
3317 Compiler: Locally scoped constants can now have an explicit type.