You can make the resource field read only in the editor:
features : {
eventEdit : {
editorConfig : {
items : {
resourceField : {
readOnly : true
}
}
}
},
Please find more info here: https://www.bryntum.com/docs/calendar/#guides/customization/eventedit.md#customizing-the-fields
Regarding the ticket. We're releasing 4.0.7 right now, and the fix is going to be a part of the next 4.0.8 release.
Cheers!