Richfaces.showModalPanel is not working with IE11 under some circumstances

IE 11
Richfaces 3.3.3.Final
JSF 1.2

Under some circumstances (in our case it is a page change, a download of a document and some other stuff), we did not figure out whats the exact problem, the javascript call Richfaces.showModalPanel() is not working anymore in IE 11. No problem with IE 10, Firefox or Chrome.

Usually you upgrade the JSF and Richfaces version to something thats maintained and forget this old stuff problems, but this was not possible for other reasons.

The solution we found is to change the code from

oncomplete="if(#{!list.errorMessages}){Richfaces.showModalPanel('myPanel');}jQuery.unblockUI();"

to

oncomplete="if(#{!list.errorMessages}){#{rich:component('myPanel')}.show()};jQuery.unblockUI();"

Now the ModalPanel is working in IE 11.