Bryntum Support Forums

Added button inside notes tab, It should be able to close the task edit popup on the button click

Hello,

You could use this https://bryntum.com/products/gantt/docs/api/Gantt/widget/TaskEditor#function-close to close the task editor.
Here is an example of how you could achieve it

button : {
    type : 'button',
    text : 'close',
    onClick : ({ source : { parent : { parent : { parent : taskEditor } } } }) => {
        taskEditor.close();
    }
}

This should be working for you.