I am not sure that I understand you right, but in case I do, you are talking about an issue with absolutely positioned images in headers/footers, which are not correctly visualized in cases where the image is moved outside of the header/footer editor area.
I have updated the item you opened:
Absolutely positioned images in headers/footers are not visualized outside of the header/footer editor area
and added the issue in our backlog. Note, however, that for now it is with relatively low priority due to its specificity.
If you have control over the docx files creation, you can set the image as a watermark as a workaround - this way it would be opened in the same way in MS Word and in RadRichTextBox.
I have added some Telerik points in your account as a token of appreciation for this bug report.
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