A panel is a flat, physical area, usually containing controls, receptacles, a display such as an LED or LCD screen, or allowing users to remove it for access to whatever lies behind it. A screen is, technically, a physical, displaying area of a panel.
A pane is a section of a window. For a physical example, a paned window is a window that is divided into sections known as panes. Originally, the meaning pertained to sectioned glass windows in walls. (Wikipedia).
Thus, panes in Word 2007 would include the title bar where it shows the names of file and of the application, a menu bar, a "ribbon" bar, the editing area, a status bar, and optional ruler bars.
Microsoft uses "task pane" to designate an area sectioned off from the main area of an application and used for some function. For example, in Excel 2007, if you click on Review, Thesaurus, Excel will divide off a portion of the editing pane to create a dialog pane so you can search for synonyms.
MS Office task panes are dockable: You can drag them to different borders of the window or leave them to float, independent of the application window. Thus, Office task panes can convert between panes and pop-up windows.
- Panes make up windows.
- Windows occupy the screen.
- The flat-panel display houses the screen.
To correct the question:
Better: There are two panes
Best: This window has two panes....
If the company style book differs, however, remember the Golden Rule: He who has the gold makes the rules.
IT Metrics and Productivity Institute (ITMPI) Premium membership gives members free access to 400 PDU-accredited webinar recordings and waives the PDU processing fees. The library is growing at about 100 webinars per year. Check it out: http://mbsy.co/dPHm?s=e