It appears that Tk 8.7a5 on linux has different processing of mouse wheel events from 8.6. On 8.6 and previous, rotating the wheel produces a ButtonPress 4 or 5 event, depending on direction of rotation. This no longer happens in 8.7a5. Is this an intentional change or a bug? Is there a list somewhere of changes in 8.7 relative to 8.6?
2022-07-21: Hi, you can now bind against <MouseWheel> event. ++
Csaba Nemethi 2022-07-21: Most of the changes related to the processing of mouse wheel events in Tk 8.7 were proposed in TIP 474 . According to this specification, in Tk 8.7a5 and later the set of mouse wheel events is the same on all windowing systems:
In addition, in Tk 8.7a5 and later a mouse wheel tick now scrolls a listbox, ttk::treeview, tablelist, etc. by 3 units, on all windowing systems. Together with the key corresponding to the Option modifier, it scrolls by 10 units.