[Feature] GUI for training data: toggle flip all selected cells into same category in one step

[larsrollik]

Is your feature request related to a problem? Please describe.
When selecting many cells/non-cells in same area (maybe dense spacing), a multi-select does not mean application of the same category assignment, but will result in each individual selection being toggled into the inverse. It is not possible to select a group that should be classified as cells or non-cells and do so in one step. - It takes very long to toggle one category individually (item by item) and then confirm the area instead of all at once.

Describe the solution you'd like
It would be convenient to select a group and on toggle move them all into one label category, so that at most two flips are required to move all of them into the desired label.

Describe alternatives you've considered
Allow toggle only category-specific, e.g. when "cells" is selected, "toggle" will only act on these.

Additional context
.

[larsrollik]

Might relate to issue #24 .

[adamltyson]

Yep, this needs to be added. Thanks @larsrollik

[adamltyson]

This functionality is now in the cellfinder napari plugin.