Leaving my dell 15 7559 connected to the AC when using?

So I want to know if is ok to leave my Dell inspiron 15 7559 connected to the AC / wall for about 9 - 11 hours I use it.

I'm asking this because I use this laptop mostly for work and to play games that requires some 3d graphics, etc. So I really don't want to go and disconnect, connect and disconnect my battery everytime is run out of power, because I know that games drain a lot of power from the battery so you need to do this a LOT of times in a day (in my case).

So that's why I'm asking if is ok to leave my laptop connected to the ac/wall those hours, or maybe disconnecting it like 1 - 2 times to discharge and charge again? I want to read some suggestions and what do you guys think.

I was reading that the new batteries the Li-ion can't be overcharged, so I doesn't matter if is at 100%, is that true?

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My laptop has a program called Dell power manager Lite (it came with the laptop), and I have this settings:

I don't know how exactly that works, if someone can explain it, would be great.

Also, there is that option called "custom", I was reading that people leaves that option to 50% and 80% fully charged, and again, I don't know how exactly that works because it says is recommended for advanced people:

I appreciate any help and suggestion. Thank you!