Show alert and prevent switching tabs when annote/abstract/rss-description contains unbalanced braces. 
Show alert and prevent switching tabs when annote/abstract/rss-description contains unbalanced braces. 

JackieXie168/skim,JackieXie168/skim,JackieXie168/skim,JackieXie168/skim,JackieXie168/skim