How to stop text disappearing when editing it in Autocad?

Question

AutoCAD

Hello!
I have: windows 8.1, licensed autocad 2009 LT and the following problem:
when editing a text block in autocad, the contents of the text block become completely or partially invisible; when zooming, this text is fully or partially displayed; at the end of editing the text - it quite exists for itself and it can already be read.

Maybe the experts from this forum faced similar problems and solved them, not necessarily in Autocad.
Thank you for your attention