Hi Gasper,
Greetings from Syncfusion.
We have checked your query “getting System.NullReferenceException - for few components: ButtonEdit and TextBoxExt”and we would like to let you know that we have added the ButtonEdit and TextBoxExt control to the VisualStudio .Net 5.0 but we are unable to reproduce the reported issue our side. Please refer the sample and video for the same.
Please check the above sample and confirm our replication is same as yours. If not please modify the sample as issue reproduceable and share Syncfusion product version details. It will be helpful to provide the prompt solution on this.
Regards,
Elakkiya