Fade Overlays Selected Icon

Hi all; Lloyd Here, using 2.1.3 on a fairly new Windows 10, HP Laptop:
Since installing 2.1.3 I have noticed the following oddity: Whenever I finish recording and break to playback to hear the latest or the selected chunk of recording, a small vertical bar appears over the playback icon and then it slowly fades to permit the icon to be activated. I’ve never seen this before except when I am using the top keys to control the sound (F6, F7, and F8 key) in other programss. I can’t understand why that vertical bar should appear unless it’s a Windows function. Do you think it is being activated by Windows or by Audacity. If by Audacity, it’s slowing me down — how do I get rid of it?
Thanks for all your continued assistance. Your prior response on using Soft Limiting was excellent.
Happy and Safe Holidays.

It does occur normally in Audacity if you press the “Ctrl” key …
vertical bar on green play triangle buttons.gif
I’ve never seen the bar “slowly fade” though: for me it disappears instantly.

You could have (inadvertently) activated an accessibility setting on Windows such as “sticky keys” which could introduce a delay.