<p>If you create two Comboboxes and tab between them you will know where the focus is by the selection. The current item will have its text selected. Change one or both to state readonly and the focus is not obvious. The only way to know which combobox widget is in focus is to try a <down-arrow> key. </p>
<pre>
ttk::combobox .cb1 -values {a b c}
ttk::combobox .cb2 -values {d e f} -state readonly
.cb1 current 0
.cb2 current 0
pack .cb1 .cb2
</pre>
<p>Have tried various work-arounds for the problem with styles but couldn't come up with anything consistent. The way that 'readonly' state currently works with comboboes makes tabbing about the interface mostly unusable.</pre>
<p>Take a look at the simple screen shot and tell me which widget has the focus. If you said the top widget you'd be wrong.</p>