The pin-sidebar action's state, being user intend for a pinned sidebar, can and will be overruled for lack of space. Currently, this overruling is made permanent, so shrinking the window and re-expanding it will result in the previously pinned sidebar to not be pinned anymore.
With decoupling the flap state from the pin-sidebar action, this overruling is made temporary with the user's previous setting restored.
As a follow-up, the button to pin the sidebar is when disabled of no use, and could even confuse due to the button's state not reflecting the sidebar's state. To solve this confusion, the button can be hidden, when the sidebar is forced into the collapsed mode on smaller screens or window widths.
changes since v1:
sidebar page toggle buttons are now of variable width
This is a follow-up to #118.
changes since v1:
wike-pin-sidebar.webm