unexpected code change in aspx file when modified in test environment

I needed to add some static text to an IIS  webpage.
I copied the production solution to a development environment.
I added the text to the appropriate .aspx file and it displays as expected in the test environment.
I used https://www.diffchecker.com/diff to check the original file and the amended file for differences.
The new text displayed as expected.
However there is one other difference which I did not introduce.
The original file has the following
<asp:FormView ID="FV_Leave" runat="server" DataSourceID="DS_LeaveDetail" DataKeyNames="ID" BorderStyle="None" style="width: 100%">

Open in new window

This has been replaced by
<asp:FormView ID="FV_Leave" runat="server" DataSourceID="DS_LeaveDetail" DataKeyNames="ID" BorderStyle="None" Height="267px" Width="1028px">

Open in new window

I have little understanding of aspx/html and am wondering how this could have happened and what possible effect this will have in production environment.
I tried commenting out the “new line” and replace it with the original in the test environment but I then get multiple validation errors.
Any guidance appreciated.
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Chinmay PatelChief Technical NinjaCommented:
Hi Blossompark,

This should not have happened. And again replacing it with the old line also should not give you any errors. The side effect of this is your FormView has hardcoded width which will not look good if any one of your client does not use 1028 width resolution. Would you please share what validation errors you are getting. I think you can safely apply style="width: 100%" without any errors.


Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
blossomparkAuthor Commented:
Hi Chinmay,
thank you....those validation errors disappeared when I inputted the code again, perhaps I had initially some syntax error
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.