Hi Rafel,
Sorry for the inconvenience caused.
We were able to reproduce the issue in column chooser while rendering ejGrid and ejTreeGrid in same page and confirmed this as bug and logged a report on this. Also we have created a support incident under your account to track the status of this issue
Please log on to our support website to check for further updates.
https://www.syncfusion.com/account/login?ReturnUrl=%2fsupport%2fdirecttrac%2fincidents
Please let us know, if you need further assistance on this.
Regards,
Dinesh kumar.N