The textfield component doesn't have a clear button by default. Instead of creating a custom MyApp.field.ClearableTextField class, you can simply use the clearbutton plugin (available in modern toolkit or via community packages in classic).
Ext.define('MyApp.plugin.RowExpander', extend: 'Ext.plugin.Abstract', alias: 'plugin.rowexpander', config: expandOnDblClick: true , extjs plugins
Creating a custom plugin involves three specific steps: The textfield component doesn't have a clear button
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