v2.1.0-beta, Small Bug with Duration-Settings

Hello

Thank you very much for sharing your great and very useful work!

I have a small bug report for v2.1.0-beta

1. I set a duration of 3 seconds. Therefore, I expect that each key is displayed for 3 seconds on the screen and then, it disappears
2. Then, I press those 3 keys: a b c

Now, there are two small bugs:

1. The keys a b do not stay 3 seconds on the screen, but are removed immediately from the screen (they should be displayed for 3 seconds)
2. The last key c remains on the screen indefinitely (it should disappear after 3 seconds)

(Even when the history is displayed, all keys should disappear after 3 seconds)

Thanks a lot, kind regards, Thomas