undo style manager with 'core:undo'

[iamkeiryan]

Hi,

Whenever I change a certain style, I use the style manager's addstyletarget. Currently, the undo is working as expected but since I have a custom field built for style change. I wanted to undo the value of it.

I checked the documentation but I can't seem to find a way to use the _previousAttributes which contains the value of the previous style.