need to refresh ui after resetting completion state

[randy3k]

a continuation of #611

[codecov-io]

Codecov Report

Merging #612 into 2.0 will increase coverage by <.01%.
The diff coverage is 100%.

@@ Coverage Diff @@ ## 2.0 #612 +/- ## ========================================== + Coverage 70.93% 70.93% +<.01%  ========================================== Files 132 132 Lines 12152 12153 +1 ========================================== + Hits 8620 8621 +1  Misses 3532 3532

Impacted Files	Coverage Δ
prompt_toolkit/buffer.py	67.83% <100%> (+0.04%)	⬆️

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[jonathanslenders]

Hi @randy3k,

Can you tell me what goes wrong without this change? Why it is needed.
I would probably like to add one or two lines documentation.

Thanks!
Jonathan

[randy3k]

If there was only one completion item and this line deleted it. The completion menu was displayed, but the complete_state was set to None . We end up with the menu popping up but the state is empty.

PS: I added two lines of comment.

[jonathanslenders]

Perfect! Thanks a lot @randy3k!