DataTrigger。存在操作未触发绑定值“null”

I have the following datatrigger, but the exitactions is not firing. The enter actions work find. I have also tried convertering the Binding to a boolean to see if it had something to do with the null, but that didn't help either. What do I have wrong and why isn't my exitactions firing here?I have the following datatrigger, but the exita