Two small-ish startup related commits
Avoid creating then immediately discarding a page's ActionButton instance
During page creation, the globalToolBarStyle property may not yet be properly initialised, which means we load and create ActionButton, then almost immediately afterwards discard it again once we know for sure we're using the ToolBar style.
This also unfolds the binding for "actionButtons.active" since it was really hard to follow.
Don't use DropShadow for overlay drawer handles
There's no need for DropShadow here, we can replace the background rectangle with ShadowedRectangle and get shadows for "free".