The bug
When you paste numbers in the text fields of the customized world generation GUI on the last page (fourth), the "Defaults" button does not become enabled.
How to reproduce
Go to the fourth page (page with the text fields) of the customized world generation settings
Paste a number in one of the text fields
The value has changed but the "Defaults" button is still disabled
Linked issues
relates to 4
MC-73066
The customization GUI initially doesn't have the 'Defaults' button enabled when recreating a world with customized settings
Resolved
MC-94499
Text fields do not deselect when clicking in another text field
Resolved
MC-95629
"Defaults" button of customized world generation always disables when "Customize" is clicked
Resolved
MC-93531
Text fields in customized world generation do not enable repeated events
Resolved
Can confirm for 1.10.2.
Related to [MC-93531] and [MC-94499]?