This problem has only begun recently. When placing an iframe into a text widget in the sidebar, it overwrites the width value in the style attribute. It’s really odd… This also only happens in the sidebar. Here’s an example page: http://www.theccsn.com/testing/ (password is thisisatestpage)
The code for the iframe is identical in the page content AND in the sidebar widget. Here is the exact code:
<div align="center"><iframe style="width: 120px; height: 240px;" marginwidth="0" marginheight="0" scrolling="no" frameborder="0" src="//ws-na.amazon-adsystem.com/widgets/q?ServiceVersion=20070822&OneJS=1&Operation=GetAdHtml&MarketPlace=US&source=ac&ref=qf_sp_asin_til&ad_type=product_link&tracking_id=chrisandcom02-20&marketplace=amazon®ion=US&placement=083082815X&asins=083082815X&linkId=NIUTXE433U6H6H7K&show_border=true&link_opens_in_new_window=true">
Please note the “width: 120px” portion. If you go to the page I linked, the iframe in the sidebar has had this changed to “width: 100%”. See this screenshot to show, definitively, the width is being modified: https://d.pr/i/s9EtMm
Also, again, please note, this ONLY applies to the sidebar. On the example page, the exact same code is placed into the page content and it is not changed.