Property value change error

Hi all,
I am using property panel extension in which allow us to create custom property. I created the custom property with custom drop down control values as following A => A, B => B and C => C. Once i save the diagram it saves the values then i load the diagram it works fine.

somehow i had to change the dropown values. Now if i open the diagram then it is generating the following error in addition that unable to load the diagram. How can i ignore this error and load diagram?

TypeError: Cannot read property ‘value’ of undefined
at http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:2988:48
at arrayEach (http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:57016:9)
at http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:59036:9
at selectbox (http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:2987:3)
at Function.EntryFactory.selectBox (http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:2836:10)
at module.exports (http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:355:34)
at createAttribTabGroups (http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:297:3)
at AttribPropertiesProvider.getTabs (http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:321:15)
at PropertiesPanel.update (http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:1037:42)
at http://localhost/app/webroot/js/properties-panel-extension/dist/index.js:867:10

issue is resolved, it was two consecutive commas , due to line break