Open up your Ext.ux.RowActions.js file and find the tplGroup/tplRow definition section and change it to this:
Code:
tplGroup:
'<tpl for="actions">'
+'<div class="ux-grow-action-item<tpl if="\'right\'===align"> ux-action-right</tpl> '
+'{cls}" style="{style}" ext:qtip="{qtip}">{text}</div>'
+'</tpl>'
,tplRow:
'<div class="ux-row-action">'
+'<tpl for="actions">'
+'<div class="ux-row-action-item {cls} <tpl if="text">'
+'ux-row-action-text</tpl>" style="{hide}{style}" ext:qtip="{qtip}">'
+'<tpl if="text"><span ext:qtip="{qtip}">{text}</span></tpl></div>'
+'</tpl>'
+'</div>'
Note the change of qtip to ext:qtip.