Underlined icon in the taskbar disappear (picture 1) and reappear

bro67 said:

Did you have any of those open when you made that screen cut?

Yes of cause

bro67 said:

Then that is why they are underlined. It is to show that they are active and have a window available to use.

I knew it.
But the problem is I sometime (as explain above) can't see underlined while in normal taskbar size (picture 1)

* picture 1 have 7 applications running but can't see underlined!

Thank You

I have updated picture 1 and 2 for easier to understand. Thank You

To : akkha

I am guessing only...…..Perhaps your taskbar icons are too large for the default taskbar size.
Go to Settings > Personalization > left side, click Taskbar > right side, turn on "Use small taskbar buttons "

Have a look at this tutorial :
Use Large or Small Taskbar Buttons in Windows 10

davidhk said:

To : akkhaI am guessing only...…..Perhaps your taskbar icons are too large for the default taskbar size.
Go to Settings > Personalization > left side, click Taskbar > right side, turn on "Use small taskbar buttons "

No it won't work.
As I mention above I can see underlined in default taskbar size.
But just sometime (about every 3 hours) it disappear...

Thank You

Problem solved

Monitor 32'' PHILIPS 323E7QDAA/00 is a culprit.

This model all have the same problem! I claim it and get money back.