MaterialCollapsible doesn't set "active" state when expanding/collapsing via mouse

[gkresic]

If MaterialCollapsibleItem is expanded via mouse click, its "active" flag is not set, so:

• MaterialCollapsible.getActive() returns null
• MaterialCollapsibleItem.isActive() returns false

One possible workaround is to check for existence of "active" CSS class name:

MaterialCollapsibleItem.getElement().hasClassName(CssName.ACTIVE)

OTOH, if item is expanded in code via MaterialCollapsible.setActive(int) then active attribute is correctly set both on MaterialCollapsible and MaterialCollapsibleItem.

[kevzlou7979]

Cool nice catch, will be updating and will patch to 2.3.1-SNAPSHOT