Remove placement guesswork, of part manipulation objects.

[Kagnaw]

Is your feature request related to a problem? Please describe.
Placement of a 'Part Manipulation Box' for example, i want to block support in a specific spot.
I have to guess the right position slice, move it, slice, adjust, slice and so on.
especially a problem in bigger parts if you want to adjust something in 3d space.

Describe the solution you'd like
Being able see and move the the modifiers/manipulations in the slice preview. Could be a toggle to show them.

Describe how it would work
I slice, i see something i don't like i make a part manipulation box (im still in the preview)
i can move the box too the spot i want to modify. Slice. Yell first tryyy and move on with my day.

Describe alternatives you've considered
Doing it by "feel" and guesswork. as i do now.

Additional context
Attached a random made upp example, i want to remove the solid at the end of the screw hole, so i could use longer ones or just to save print time.

[neophyl]

So basically a duplicate of either #3678 (which I remember as I created it) :) or #4438 which has some nice example graphics included.

[Kagnaw]

Ahh yes indeed, i see my search for similar requests failed quite badly, as there are many others.

I guess the only difference in my is that i would like to see and move modifier in the sliced preview to more easily place it right on the thing i want to modify.