Thanks for letting me know about this.
I was able to reproduce the effect by assigning some padding to the form table.
That table may well require more space than is available in some fixed-width themes, or on some small tablets.
When EntryWizard was first released, there were a few people who did not notice the horizontal scrollbar. That is why I added the warning. Unfortunately, there is no direct way for the code to detect whether that scrollbar is actually visible — it has to second-guess the browser based on the widths it can see.
Most likely your theme is adding padding to the table (which would show as blank space, so the whole table would appear to be visible). Try setting the padding to 0 for class “ewz_upload_table” in css. I’ll do that for the next release.
I’ll also give it a bit more leeway, so the message only kicks in if the table is more than a couple of pixels too wide to fit.