diff --git a/src/main/scala/li/cil/oc/util/FontUtils.scala b/src/main/scala/li/cil/oc/util/FontUtils.scala
index 08f691192..2d63ddfc2 100644
--- a/src/main/scala/li/cil/oc/util/FontUtils.scala
+++ b/src/main/scala/li/cil/oc/util/FontUtils.scala
@@ -154,6 +154,7 @@ object FontUtils {
       try {
         var line: String = null
         val input = new BufferedReader(new InputStreamReader(font, StandardCharsets.UTF_8))
+        var out_of_range_glyph: Int = 0
         while ({line = input.readLine; line != null}) {
           val info = line.split(":")
           val charCode = Integer.parseInt(info(0), 16)
@@ -164,9 +165,15 @@ object FontUtils {
               case n => OpenComputers.log.warn(s"Invalid glyph size detected in font.hex. Expected 64 or 32, got: $n")
             }
           } else {
-            OpenComputers.log.warn(f"Invalid glyph char code detected in font.hex. Expected 0<= charCode <$codepoint_limit%X, got: $charCode%X")
+            if (out_of_range_glyph == 0) {
+              OpenComputers.log.warn(f"Invalid glyph char code detected in font.hex. Expected 0<= charCode <$codepoint_limit%X, got: $charCode%X")
+            }
+            out_of_range_glyph += 1
           }
         }
+        if (out_of_range_glyph > 1) {
+          OpenComputers.log.warn(f"${out_of_range_glyph} total invalid glyph char codes detected in font.hex")
+        }
       } finally {
         try {
           font.close()
diff --git a/src/main/scala/li/cil/oc/util/TextBuffer.scala b/src/main/scala/li/cil/oc/util/TextBuffer.scala
index 8cef8bad6..31503ae80 100644
--- a/src/main/scala/li/cil/oc/util/TextBuffer.scala
+++ b/src/main/scala/li/cil/oc/util/TextBuffer.scala
@@ -166,6 +166,8 @@ class TextBuffer(var width: Int, var height: Int, initialFormat: PackedColor.Col
       case dx if tx > 0 => dx
       case dx => dx.swap
     }
+    val left_edge = math.min(dx0, dx1) - 1
+    if (left_edge >= width - 1) return false // no work
     val (dy0, dy1) = (math.max(0, math.min(height - 1, row + ty + h - 1)), math.max(0, math.min(height, row + ty))) match {
       case dy if ty > 0 => dy
       case dy => dy.swap
@@ -186,11 +188,17 @@ class TextBuffer(var width: Int, var height: Int, initialFormat: PackedColor.Col
               nl(nx) = ol(ox)
               nc(nx) = oc(ox)
               for (offset <- 1 until FontUtils.wcwidth(nl(nx))) {
-                nl(nx + offset) = ol(' ')
+                nl(nx + offset) = ' '
                 nc(nx + offset) = oc(nx)
               }
             case _ => /* Got no source column. */
           }
+          // any wide chars along the left edge of the target rectangle need to be cleared
+          // don't change their colors
+          if (left_edge >= 0 && FontUtils.wcwidth(nl(left_edge)) > 1) {
+            nl(left_edge) = ' '
+            changed = true
+          }
         case _ => /* Got no source row. */
       }
     }
@@ -202,16 +210,16 @@ class TextBuffer(var width: Int, var height: Int, initialFormat: PackedColor.Col
       // Don't allow setting wide chars in right-most col.
       return
     }
-    if (x > 0 && line(x) == ' ' && FontUtils.wcwidth(line(x - 1)) > 1) {
-      // Don't allow setting the cell following a wide char.
-      return
-    }
     line(x) = c
     lineColor(x) = packed
     for (x1 <- x + 1 until x + FontUtils.wcwidth(c)) {
       line(x1) = ' '
       lineColor(x1) = packed
     }
+    if (x > 0 && FontUtils.wcwidth(line(x - 1)) > 1) {
+      // remove previous wide char (but don't change its color)
+      line(x - 1) = ' '
+    }
   }
 
   def load(nbt: NBTTagCompound): Unit = {