I discovered that Origin Project Explorer is no longer showing the windows in each project folder. I have no explanation, and have been through the "view" and "right click" menus a number of times to recover the ability to access windows.
For example in the attachment, I want to be able to see the windows "Graph 6" and "originaltrunc" in the Project Explorer window under the folder "Truncated data comp." I have the right click pop up window also showing.
There are two panels in Project Explorer. Top and Bottom by default.
Maybe somehow you dragged the splitter so it was to the bottom of the PE. Could you try mouse over the bottom of PE and see if there is a splitter you could drag up?
Or could you choose View: Toolbars... menu. With Toolbars tab active, click Reinitialize button.
It should restore all toolbar and dockable windows to default setting.
BTW, in Origin 2015, we made a lot of PE improvements. E.g. you can view extra large icon view of graph windows without activating each graph. http://originlab.com/2015