I've checked in [ec38f729fa]:

1. Return type of Tk_CreateBinding changed to 'Mask', because the return value is am event mask. This change is binary compatible, because 'Mask' is an alias for 'unsigned long' (old return type).

2. Issue with homogeneous equal sequences fixed, see this script:

            bind . <1><Control-1> { lappend x "first" }<br/>
            bind . <Control-1><1> { lappend x "last" }<br/>
            event generate . <Control-1><br/>
            event generate . <Control-1><br/>
            set x

This script should return "last" due to manual. Legacy implementation is failing this test case. See new test cases bind-33.12 and bind-33.13.

I'm about to finish the TIP, will come soon.

Please do a test under Windows.