Unexpected null value [Bug]

[adultcode]

I tried all the examples they work well but every of theme give me this error in terminal

First error

Container(constraints: BoxConstraints(w=600.0, h=500.0)):
Unexpected null value.

Second error

The following assertion was thrown during performLayout():
Each child must be laid out exactly once.

Code

Scaffold(
      appBar: AppBar(),
      body:   Container(
         constraints: BoxConstraints(
           minHeight: 500,maxHeight: 500,
           minWidth: 600,maxWidth: 600
         ),
        child: PlutoGrid(
            columns: columns,
            rows: rows
          createFooter: (stateManager) {
            stateManager.setPageSize(10, notify: false); // default 40
            return PlutoPagination(stateManager);
          },
            onChanged: (PlutoGridOnChangedEvent event) {
              print(event);
            },
          ),
      ),
    );

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This issue is stale because it has been open for 30 days with no activity.

[github-actions[bot]]

This issue was closed because it has been inactive for 14 days since being marked as stale.