Sencha upgrade to 5.1 GPL

I upgraded my sencha app into 5.1, I don't get any errors during the build process, but the web page is blank - the error message says

Uncaught Error: Cannot override method startEdit on Ext.grid.plugin.CellEditing instance.

I use a propertygrid in my application.

I can't also use sparklineline because it says i'm registering duplicate components with the id 'sparkline-tooltip'

did anyone run into a similar issue ?

Sencha upgrade to 5.1 GPL