In more detail: Unchecking "Start Dropbox on system startup" and "Open the desktop app when you start Dropbox" causes Dopbox to continue to start on system startup but prevents it from opening the Dropbox folder in the Windows Explorer upon startup.
In more detail: Unchecking "Start Dropbox on system startup" and "Open the desktop app when you start Dropbox" causes Dopbox to continue to start on system startup but prevents it from opening the Dropbox folder in the Windows Explorer upon startup.