If I open in Creo Illustrate two different files "3CDI", then how can I switch between their open windows (shortcut "Tab", "Alt+Tab" does not work)?
You're not really opening two files at once. When you do File -> Open, currently opened illustration gets closed.
You can run multiple Creo Illustrate instances and open different files in each instance.
Dmitry Tsarev wrote:
...You can run multiple Creo Illustrate instances and open different files in each instance...
In this case it is necessary to have in a license file more license keys ("Qty" = Quantity) for Creo Illustrate .
This is the only way (I'm aware of) to achieve the functionality you're looking for
However, in Creo Parametric 1.0 is available a simple option "Windows". I do not think that it was so hard to do the same for Creo Illustrate 1.0.
"Windows" in Creo Parametric 1.0: