Intrusive browser window coming into focus.

[Wicky]

I often have multiple Chrome browser windows open, with multiple tabs open in each. I'm repeatedly having an issue where a back (dormant) window will force itself to the front (focus). I can live with it but it's annoying because it sometimes happens at a very inconvenient moment, eg. just as I click the return key while submitting a form.

Has anybody else had the same issue, or know how to stop it from happening.

 

[rpmurray]

Spunds like you have some malware running. You may want to run Malwarebytes or similar to see what it is.

 

[Honza1]

Either malware as noted above or some extension in Chrome is behaving like malware.
Check all extensions and understand what they are doing and what you "pay" for it. Many will do something marginally useful (like check web for cheaper price when shopping) at significant cost (running bitcoin mining or spying on you or whatever). Delete or disable those which looks suspicious and see if it keeps happening.