And why cant i write it easy ??
On any window with a table view where the rows have checkboxes, like the Buy-in Players window, or the Bust Players out window, or the Add-on Players or Rebuy Players window in your video, clicking anywhere on the highlighted line will toggle the checkbox. This is a convenience feature. That window is slightly different because it also has a numeric input for the Quantity, which is only enabled when the checkbox is checked. So if the checkbox is not checked, the input is disabled and you can't select it or edit it.
The TD is coded specifically so that clicking within the input won't toggle the checkbox. It would be very annoying if simply clicking in the input so that it has focus so you can change the quantity toggled the checkbox off, which in turn disabled the input. But that is exactly what is happening in your video.
From what I can see technically, pressing your mouse button down on the input, then moving your mouse outside of the input but leaving it on the same row, and then releasing your mouse generates an event that amounts to a click on the row. So the new framework is handling this type of action differently than the old one. I'll have to investigate it a little further in order to see how to fix it. Definitely a bug.
Thanks for posting this, and thanks for the video. Video is very helpful in identifying an issue quickly. Until I can fix it I suggest simply clicking in the input and using the DEL key to delete the current value, or double-clicking the value in the input to select it instead.