Thanks for using Notezilla .
You can use the below options to avoid creating a sticky note.
Single click option on the tray icon will open the notes browser, if you choose the below first option. Also new note will be created directly inside the specified memoboard if you choose the second option (below).

You can also mark a memoboard as favorite and use the Favorite memoboard from below menu. Right click on Notezilla icon (next to the clock) in the taskbar and select Notes Browser or Favorite memoboard option from the menu
