Delete empty notes in docear

Preview added bookmarks cannot be read by docear. I deleted all of them.

But docear will still read the preview added bookmarks as empty notes. 

I still don't know how to delete the marks added by preview to the pdf files. 

Here is the work around. After importing the bookmarks in decear, save and reopen in decear. Then use filter Matches regexp ^.{0,1}$ to find out all the empty notes. Then select all matches notes in the Filter menu. Press Del on the keyboard to delete all of them.

--
Feng