Fix button rendering

src/main/java/appeng/client/gui/widgets/GuiImgButton.java

@@ -23,7 +23,6 @@ import appeng.api.config.*;
 import appeng.core.localization.ButtonToolTips;
 import com.mojang.blaze3d.systems.RenderSystem;
 import net.minecraft.client.Minecraft;
-import net.minecraft.client.gui.widget.Widget;
 import net.minecraft.client.gui.widget.button.Button;
 import net.minecraft.client.renderer.texture.TextureManager;
 import net.minecraft.util.ResourceLocation;
@@ -189,6 +188,7 @@ public class GuiImgButton extends Button implements ITooltip
 			TextureManager textureManager = minecraft.getTextureManager();
 			textureManager.bindTexture(TEXTURE_STATES);
 			RenderSystem.disableDepthTest();
+			RenderSystem.enableBlend(); // FIXME: This should be the _default_ state, but some vanilla widget disables it :|
 			if( this.halfSize )
 			{
 				this.width = 8;

src/main/java/appeng/client/gui/widgets/GuiTabButton.java

@@ -91,10 +91,9 @@ public class GuiTabButton extends Button implements ITooltip
 			{
 				this.itemRenderer.zLevel = 100.0F;
 
-				RenderSystem.enableDepthTest();
-//	FIXME			RenderHelper.enableGUIStandardItemLighting();
+				RenderHelper.enableStandardItemLighting();
 				this.itemRenderer.renderItemAndEffectIntoGUI( this.myItem, offsetX + this.x + 3, this.y + 3 );
-				RenderSystem.disableDepthTest();
+				RenderHelper.disableStandardItemLighting();
 
 				this.itemRenderer.zLevel = 0.0F;
 			}