You may run into problems if you have a dark CSS background color for your site which is defined on the body element. The ActiveX control will show this dark color as its background color even if it is a child of another element with a light background color. This makes it difficult , if not impossible, to read and work with the content in the control.
On tinyfly.com I’ve found the solution for this:
/* Background color for ActiveX items like “Edit in Datasheet */
/* real background color for the site as a whole */
/* to be sure it fills the whole page vertically */