Text fields in customized world generation do not enable repeated events

The bug

The text fields for the customized world generation (page four) do not enable repeated events for the keyboard. What this means is that you cannot hold down for example backspace and remove the complete input. Instead you have to press a key every time you want to activate it. As far as I know this is the only GUI where it is not explicitly enabled (based on MCP 1.8).

Code analysis

Code analysis by [Mod] bemoty can be found in this comment.