Yes it's possible to remove some part of the selection
But you need first to close the selection, then hit "Enter"
Then in the option tool click on the button "Substract" (yellow arrow on the screenshot), then hit "Enter" once you've substracted
The green arrow is the "Addition" mode (if you have removed too much for example), same as above hit "Enter once you have add a part of a selection
The last but not the least, Never forget to click back on the "single" (normal) mode (red arrow) once you have finished, or next time you might ask yourself why the free select tool does not work as expected
(those mode works (substract/addition/intersect) also with the Rectangle and ellipse tool as well as with the Fuzzy select tool, or any already made selection)
But you need first to close the selection, then hit "Enter"
Then in the option tool click on the button "Substract" (yellow arrow on the screenshot), then hit "Enter" once you've substracted
The green arrow is the "Addition" mode (if you have removed too much for example), same as above hit "Enter once you have add a part of a selection
The last but not the least, Never forget to click back on the "single" (normal) mode (red arrow) once you have finished, or next time you might ask yourself why the free select tool does not work as expected
(those mode works (substract/addition/intersect) also with the Rectangle and ellipse tool as well as with the Fuzzy select tool, or any already made selection)