Fix HighlightManager not respecting optionals.

src/com/dmdirc/config/ConfigBinder.java

@@ -26,6 +26,7 @@ import com.dmdirc.DMDircMBassador;
 import com.dmdirc.events.AppErrorEvent;
 import com.dmdirc.interfaces.config.AggregateConfigProvider;
 import com.dmdirc.interfaces.config.ConfigChangeListener;
+import com.dmdirc.interfaces.config.ReadOnlyConfigProvider;
 import com.dmdirc.logger.ErrorLevel;
 import com.dmdirc.util.collections.MapList;
 
@@ -165,6 +166,7 @@ public class ConfigBinder {
             final Class<?> targetClass) {
         if (targetClass.equals(String.class)) {
             return manager.getOptionString(getDomain(binding.domain()), binding.key(),
+                    binding.required(), ReadOnlyConfigProvider.PERMISSIVE_VALIDATOR,
                     binding.fallbacks());
         }
 

src/com/dmdirc/config/ConfigBinding.java

@@ -63,6 +63,15 @@ public @interface ConfigBinding {
      */
     boolean applyInitially() default true;
 
+    /**
+     * For settings that support fallbacks, whether or not a value is required. If it is not
+     * required, a "false:" setting will result in {@code null} being returned, rather than
+     * the next fallback being tried.
+     *
+     * @return True if the setting is required, false otherwise.
+     */
+    boolean required() default true;
+
     /**
      * {@link Invocation} class that will be created and used to execute the config binding.  The
      * default just directly executes or sets the value.

src/com/dmdirc/ui/messages/HighlightManager.java

@@ -58,7 +58,7 @@ public class HighlightManager {
 
     private Optional<Pattern> nicknamePattern = Optional.empty();
 
-    private Optional<Colour> backgroundColour = Optional.of(Colour.RED);
+    private Optional<Colour> backgroundColour = Optional.empty();
     private Optional<Colour> foregroundColour = Optional.empty();
 
     public HighlightManager(
@@ -111,7 +111,7 @@ public class HighlightManager {
                 .ifPresent(this::setNickname);
     }
 
-    @ConfigBinding(domain = "ui", key = "highlightLineForegroundColour")
+    @ConfigBinding(domain = "ui", key = "highlightLineForegroundColour", required = false)
     void handleForegroundColour(final String value) {
         if (Strings.isNullOrEmpty(value)) {
             foregroundColour = Optional.empty();
@@ -120,7 +120,7 @@ public class HighlightManager {
         }
     }
 
-    @ConfigBinding(domain = "ui", key = "highlightLineBackgroundColour")
+    @ConfigBinding(domain = "ui", key = "highlightLineBackgroundColour", required = false)
     void handleBackgroundColour(final String value) {
         if (Strings.isNullOrEmpty(value)) {
             backgroundColour = Optional.empty();