Is it possible to have two property layer dialogs open at the same time? I would like to see the properties of two layer's fields at the same time. I need this because when I want to join two layers by a common field I like to check they are of the same type. I am using 2.18.11.
No, the property dialog is modal (i.e. you can have just one open and you can't do anything else while it is open).
However, when setting the join, you have access to important information about the datatype.
123 for integers,
1.2 for floats,
abc for string etc. I don't know whether they agreagate multiple types or not (ex: