Hi,
Nice project!

Bugs:
Designer

Use shift control for select multiple are control of control key

Left,Top doesn't accept negative value

Change Left value and hit enter doesn't any effect

Some controls doesn't have number when add in window

Button1,Button2,Button3 OK
ComboBox,ComboBox,ComboBox NOT (same PopupMenu,....)

Change window size doesn't update bound blue rectangle

Can have 2 windows with same name!

Print keyword not colored in code

Add a constant in window1 crash:

Fatal VM exception: System.InvalidCastException: Expected Class but got Integer.
Fatal VM exception: System.InvalidCastException: Expected Class but got Integer.
at Objo.VM.Value.ThrowInvalidCast(ObjoType expected)
at Objo.VM.Value.get_AsClass()
at Objo.VM.VM.Run(Int32 exitAtFp)
at Objo.VM.VM.Execute(ObjoClosure closure)
at Objo.Host.Desktop.Program.<>cDisplayClass0_0.<Main>b5()