CorelDRAW X5 :: Text Partially Disappears?

Since uprading to X5, virtually every file with text that I open has a problem.  All text (artistic or paragraph) is visible when selected with Pick Tool  but when Text Tool is selected, the text  "disappears" either partially or totally.  Very difficult to edit!  Invisible text areas can be highlighted but not seen.

On the same page, when editing different different blocks of text, some have become totally invisible, or, just at the bottom of a paragraph, or just as a strip down the right hand side of artistic text (almost as though a white box was placed over it).  Where there is a red underline, indicating a possible spelling mistake, the red line is still visible althought the text is not!

It is invisible in any Text Tool View - Enhanced - Wireframe etc.

Text reappears if I click on bottom middle handle (eg to flow to another paragraph) but as soon as released, it disappears again.

Ctrl W works rarely and only partially.  I have tried different basic fonts with exactly same results. (eg Arial, Times NR)

Select text with Pick tool and there is full text again.

In the nature of my business I hardly have a file without text in it!