We fixed it by changing any if statement that said
if((e.button == 2)
to
if(e.button==2 || (e.which == 1 && e.metaKey == true))
in webui.js and the init.js of the extsearch plugin
webui.js: lines 439, 783, 889, 1061, 1162, 1615, 1639, 2047, 2071
extsearch/init.js: lines 412, 557