tinymce-docs/_includes/configuration/min_width.md

min_width

This option allows you to set the minimum width that a user can stretch the entire {{site.productname}} interface (by grabbing the dragable area in the bottom right of the editor interface) when using the modern theme.

Note: This behavior is different from the autoresize plugin, which controls the resizing of the editable area only, not the entire editor.

Type: Number

Example: Using min_width

tinymce.init({
  selector: 'textarea',  // change this value according to your HTML
  min_width: 400
});

Note: By default the resize handle does not allow horizontal dragging and giving this key a value will not result in an observable behavior.