If you are using widget column (Ext.grid.column.Widget class) with content grid you will get error “Uncaught TypeError: Cannot read property ‘isModel’ of null” on clicking on the cell of the child grid.

 

To solve this problem you will need the following override the ‘Ext.grid.CellContext’ class. This bug takes place in ExtJs versions 6.0 – 6.3. Put the following override in ‘/override/grid/CellContext.js’ file and rebuild your project.

 

Working sample: