diff --git a/Terminal/Terminal.cpp b/Terminal/Terminal.cpp
index 4d0c8aae6e..0fd39e7c25 100644
--- a/Terminal/Terminal.cpp
+++ b/Terminal/Terminal.cpp
@@ -75,10 +75,22 @@ Terminal::Line::~Line()
 
 void Terminal::Line::clear(Attribute attribute)
 {
-    dirty = true;
-    memset(characters, ' ', length);
-    for (word i = 0 ; i < length; ++i)
+    if (dirty) {
+        memset(characters, ' ', length);
+        for (word i = 0 ; i < length; ++i)
+            attributes[i] = attribute;
+        return;
+    }
+    for (unsigned i = 0 ; i < length; ++i) {
+        if (characters[i] != ' ')
+            dirty = true;
+        characters[i] = ' ';
+    }
+    for (unsigned i = 0 ; i < length; ++i) {
+        if (attributes[i] != attribute)
+            dirty = true;
         attributes[i] = attribute;
+    }
 }
 
 Terminal::~Terminal()
diff --git a/Terminal/Terminal.h b/Terminal/Terminal.h
index 5a81b410c9..e5e7d81f34 100644
--- a/Terminal/Terminal.h
+++ b/Terminal/Terminal.h
@@ -70,6 +70,10 @@ private:
         {
             return foreground_color == other.foreground_color && background_color == other.background_color;
         }
+        bool operator!=(const Attribute& other) const
+        {
+            return !(*this == other);
+        }
     };
 
     struct Line {