"The Commit that properly implements the disabling of Gui Elements"

Added enabled Field to DelegatingElement, which every instance can handle itself
Made isEnabled Field in GuiAdvancedTextField protected for subclasses to access
Made GuiDraggingNumberInput only draggable while enabled
Made GuiDropdown check enabled field before accepting mouse clicks
Properly tints GuiTexturedButton if disabled

src/main/java/eu/crushedpixel/replaymod/gui/elements/DelegatingElement.java

@@ -3,6 +3,9 @@ package eu.crushedpixel.replaymod.gui.elements;
 import net.minecraft.client.Minecraft;
 
 public abstract class DelegatingElement implements GuiElement {
+
+    protected boolean enabled = true;
+
     public static DelegatingElement of(final GuiElement element) {
         return new DelegatingElement() {
             @Override
@@ -55,5 +58,7 @@ public abstract class DelegatingElement implements GuiElement {
     }
 
     @Override
-    public void setEnabled(boolean enabled) {}
+    public void setEnabled(boolean enabled) {
+        this.enabled = enabled;
+    }
 }