igCombo _customCallback() override

[mmart1n]

Description

Overriding the igCombo.options.dataSource.settings.callback function through the datasoure callback property is impossible.

• ignite-ui version: 2018.1
• browser: all browsers

Steps to reproduce

1. add ui.igCombo()
2. override igCombo.options.dataSource.settings.callback

Result

dataSource.settings.callback never calls the function set by the developer, but falls back to its default function.

Expected result

dataSource.settings.callback to call the function set by the developer