diff --git a/unix/KasmVNC/ConfigKey.pm b/unix/KasmVNC/ConfigKey.pm
index f60fd63..b8ff425 100644
--- a/unix/KasmVNC/ConfigKey.pm
+++ b/unix/KasmVNC/ConfigKey.pm
@@ -32,13 +32,6 @@ sub validate {
 
   return if $self->isValueBlank();
 
-  if ($self->{validator}) {
-    $self->resolveValidatorFromFunction() if (ref $self->{validator} eq "CODE");
-
-    $self->{validator}->validate($self);
-    return;
-  }
-
   switch($self->{type}) {
     case INT {
       $self->validateInt();
@@ -47,6 +40,13 @@ sub validate {
       $self->validateBoolean();
     }
   }
+
+  if ($self->{validator}) {
+    $self->resolveValidatorFromFunction() if (ref $self->{validator} eq "CODE");
+
+    $self->{validator}->validate($self);
+    return;
+  }
 }
 
 sub resolveValidatorFromFunction {
diff --git a/unix/kasmvnc_defaults.yaml b/unix/kasmvnc_defaults.yaml
index afad666..0ed63ce 100644
--- a/unix/kasmvnc_defaults.yaml
+++ b/unix/kasmvnc_defaults.yaml
@@ -134,6 +134,10 @@ encoding:
   compare_framebuffer: auto
   zrle_zlib_level: auto
   hextile_improved_compression: true
+  scrolling:
+    detect_vertical_scrolling: false
+    detect_horizontal_scrolling: false
+    scroll_detect_threshold: 25%
 
 server:
   http:
diff --git a/unix/vncserver b/unix/vncserver
index 1ac99c8..7a9588f 100755
--- a/unix/vncserver
+++ b/unix/vncserver
@@ -1246,6 +1246,10 @@ sub DefineConfigToCLIConversion {
     pattern => qr/^(never|\d+)$/,
     errorMessage => "must be a number or 'never'"
   });
+  my $percentValidator = KasmVNC::PatternValidator->new({
+    pattern => qr/^(\d+%)$/,
+    errorMessage => "must be a number, followed by %"
+  });
   my $allConfigKeysValidatorSub = sub {
     my @allConfigKeys = map { $_->configKeyNames() } @xvncOptions;
 
@@ -1253,6 +1257,14 @@ sub DefineConfigToCLIConversion {
       allowedValues => [flatten(@allConfigKeys)]
     })
   };
+  my $deriveValueStripPercentSub = sub {
+    $self = shift;
+
+    my $value = $self->configValue();
+    $value =~ s/%$//;
+
+    $value;
+  };
   KasmVNC::CliOption::beforeIsActive(\&limitVncModeOptions);
   my $ipv4_regexp = '((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.|$)){4}';
   my $ipv6_regexp = '(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4}){0,1}:){0,1}((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]))';
@@ -1999,20 +2011,10 @@ sub DefineConfigToCLIConversion {
         configKeys => [
           KasmVNC::ConfigKey->new({
             name => "encoding.video_encoding_mode.enter_video_encoding_mode.area_threshold",
-            validator => KasmVNC::PatternValidator->new({
-              pattern => qr/^(\d+%)$/,
-              errorMessage => "must be a number, followed by %"
-            }),
+            validator => $percentValidator
           })
         ],
-        deriveValueSub => sub {
-          $self = shift;
-
-          my $value = $self->configValue();
-          $value =~ s/%$//;
-
-          $value;
-        }
+        deriveValueSub => $deriveValueStripPercentSub
     }),
     KasmVNC::CliOption->new({
         name => 'VideoOutTime',
@@ -2462,6 +2464,56 @@ sub DefineConfigToCLIConversion {
           })
         ]
     }),
+    KasmVNC::CliOption->new({
+        name => 'DetectScrolling',
+        configKeys => [
+          KasmVNC::ConfigKey->new({
+            name => "encoding.scrolling.detect_vertical_scrolling",
+            type => KasmVNC::ConfigKey::BOOLEAN
+          })
+        ],
+        isActiveSub => sub {
+          $self = shift;
+
+          my $value = $self->configValue();
+          isPresent($value) && $value eq 'true';
+        }
+    }),
+    KasmVNC::CliOption->new({
+        name => 'DetectHorizontal',
+        configKeys => [
+          KasmVNC::ConfigKey->new({
+            name => "encoding.scrolling.detect_horizontal_scrolling",
+            type => KasmVNC::ConfigKey::BOOLEAN,
+            validator => KasmVNC::CallbackValidator->new({
+              isValidCallback => sub {
+                my $value = shift;
+
+                return 1 if $value eq "false";
+
+                ConfigValue("encoding.scrolling.detect_vertical_scrolling") eq "true";
+              },
+              errorMessage => "Detection of horizontal scrolling requires detection of vertical scrolling enabled"
+            }),
+          })
+        ],
+        isActiveSub => sub {
+          $self = shift;
+
+          my $value = $self->configValue();
+          isPresent($value) && $value eq 'true';
+        }
+    }),
+    KasmVNC::CliOption->new({
+        name => 'ScrollDetectLimit',
+        configKeys => [
+          KasmVNC::ConfigKey->new({
+            name => "encoding.scrolling.scroll_detect_threshold",
+            validator => $percentValidator
+          })
+        ],
+        deriveValueSub => $deriveValueStripPercentSub
+    }),
   );
 
   %cliArgMap = map { ("-" . $_->{name}) => $_ } @xvncOptions;
diff --git a/unix/xserver/hw/vnc/Xvnc.man b/unix/xserver/hw/vnc/Xvnc.man
index 206784c..2afd1fa 100644
--- a/unix/xserver/hw/vnc/Xvnc.man
+++ b/unix/xserver/hw/vnc/Xvnc.man
@@ -584,6 +584,23 @@ When this option is used, benchmarking results can be saved to a file specified
 .B -BenchmarkResults <results_file.xml>
 Save the benchmarking results to the specified file.
 Use this option together with \fB-Benchmark\fP to output the report to a custom file.
+.
+.TP
+.B \-DetectScrolling
+Try to detect scrolled sections in a changed area.
+
+Detect vertical scrolling on the screen and then use copyRects instead of
+sending jpeg.  A copy rect tells the client to copy a section of the screen and
+paste it somewhere else. This significantly reduces bandwidth usage when someone
+is scrolling down a page.
+.
+.TP
+.B \-DetectHorizontal
+With \fB-DetectScrolling\fP enabled, try to detect horizontal scrolls too, not just vertical.
+.
+.TP
+.B \-ScrollDetectLimit
+At least this % of the screen must change for scroll detection to happen, default 25.
 
 .SH USAGE WITH INETD
 By configuring the \fBinetd\fP(1) service appropriately, Xvnc can be launched