I've always thought that a contextual click (aka right-click) on an object should select the object if it's not already selected while bringing up a contextual menu. But lately I've noticed a variation of that behavior from both Apple and Microsoft. Instead of changing the selection, there is a secondary selection that only applies to the contextual menu.
Here is an example with Mac OS 10.10's Finder:
The blue fill on Dictionary shows the selection prior to the right-click. The blue outline on Calendar shows the temporary selection for the contextual action.
And here's an example from Microsoft Outlook 2013:
The gray fill shows the previous selection and the dotted outline shows the temporary selection.
I can see the appeal of this behavior since it allows you to apply an action to an object without losing the current selection, but I can't find any documentation about it. Other apps I sampled still have the single selection model, including Windows 7 File Explorer and Visual Studio 2015.
I can find reference to the select-object-on-context-click in the Windows 7 UX Guidelines:
Single right click: Selects the object and displays its context menu.
But I haven't found any guidelines for the newer secondary selection feature.
Question: Are there UX guidelines that discuss the use of a secondary selection for contextual menus?