How to control the tkinter combobox selection highlighting
You can use the Combobox's selection_clear() method to clear the selection whenever you want. e.g
inUnitsValue.selection_clear()
Could it be that with a readonly combobox the problem is not the selection but the relatively strong focus-indicator?
With this workarround you lose the ability to control your program by keyboard. To do it right you would have to change the style of the focus-highlighting.
from tkinter import *from ttk import *def defocus(event): event.widget.master.focus_set()root = Tk()comboBox = Combobox(root, state="readonly", values=("a", "b", "c"))comboBox.grid()comboBox.set("a")comboBox.bind("<FocusIn>", defocus)mainloop()