The bug

When you do a tellraw command with a hoverEvent and you specify a color (such as specified below), the color only works along the first line.

/tellraw @p [{"text":"Hover!","hoverEvent":{"action":"show_text","value":[{"text":"Green text\nNot green text","color":"green"}]}}] 

When hovered, should show

instead of

Code analysis

Based on 1.11.2 decompiled using MCP 9.35 rc1

This happens because the method net.minecraft.client.gui.GuiScreen.handleComponentHover(ITextComponent, int, int) just splits the text at line breaks and then renders each line separately. Therefor the second line has no formatting anymore. Instead the method net.minecraft.client.gui.GuiUtilRenderComponents.splitText(ITextComponent, int, FontRenderer, boolean, boolean) could be used.