Mouse hover never opens a site unless the user clicks on the link or one has bad mouse buttons. The feature comes from the mouse driver or OS loaded driver's that tell what the mouse does or responds to clicks.

No, it's not a problem with mouse buttons: it is a 'feature' of some webpages.

What if you disable pop-up permission for the site? Here's how:

While you are on a page on the site, call up the Page Info dialog using one of these methods:

• Ctrl+i (for Mac, Command+i)
• (menu bar) Tools > Page Info
• click the lock icon in the address bar, on the drop-down click the > button, then at the bottom click "More Information"

When the dialog comes up, click the Permission icon at the top to show that panel.

Scroll down to "Open pop-up windows" and uncheck the "Use default" box, and then select Block.

This change is saved automatically in regular windows, so you can close this dialog now. Note: it might only be saved for the rest of the session in private windows.