I assume this is a sitebuilder tool. Could you mention which sitebuilder it is?

Is the problem that a paste button provided by the sitebuilder does nothing when you click it? This could be related to a Firefox security feature that bars sites from reading your Windows clipboard. Or it could just be broken. If it's a sitebuilder button, I could look into past threads for possible solutions/workarounds.

For pasting text, instead of using a button provided by the sitebuilder, can you use one of the Windows shortcuts?

• Ctrl+v
• right-click > Paste
• Edit menu > Paste (if you use the classic menu bar)

That might not work with images...

Finally, I will say that Internet Explorer 11 is a pretty solid product. If you need to use it for your website builder tool because it only works well in IE, I don't think you are taking a lot of security risk there. Just don't stray over to random sites you don't trust.

By the way, some sites do not work correctly when you turn on the feature to warn you before the page is reloaded or redirected. If you find yourself mysteriously stuck when submitting data to a site, it's worth trying again with that feature turned off.

orange Firefox button (or Tools menu) > Options > Advanced

On the "General" mini-tab, uncheck the box for "Warn me when websites try to redirect or reload the page"