Finder not showing toolbar and sidebar sometimes I'm running OS X 10.8.2 with TotalFinder.

Recently, when launching Finder from dock stacks—for instance, the Downloads folder—by clicking the "Open in Finder", the toolbar and sidebar are both hidden (I have them visible by default).

I can't find an option for that. Is this a bug?
You should check, if you have View -&gt; Show Toolbar option enabled. When toolbar is disabled, there's no option to have sidebar and "Show Sidebar" option in Finder Menu View -&gt; Show Sidebar is grayed out. 

Worked for me.