How to keep selected text highlighted when focus changes in MS Word

When I select text Microsoft Word (2003, 2007, 2010) it shows up highlighted. However, when I change focus to another program, the highlighted text is no longer highlighted (until Word is again having focus). Is there a way to change this, i.e. that the selection is visible even then another application or form has focus.
Note, that I don’t wish to resolve this by e.g using VBA WordApl. Activate which would force focus back to Word, and hence make the selection visible.
I’m creating an Word add-in which at some point need to select some text in Word document. However, when user click on the add-in interface form, the selection is not visible, until focus is returned back to Word document, which is bad for me. On the other hand, if you for instance use Word spellchecker, when it finds unknown word and it selects it, the selection is visible even if you currently work with the spellchecker form (i.e. when the spellchecker form has focus); I need to replicate such a behavior, i.e. that the selection in Word is visible event when the user is working with add-ins form…