diff --git a/toonz/sources/tnztools/brushtool.cpp b/toonz/sources/tnztools/brushtool.cpp
index 1585aa8..6b5a5b2 100644
--- a/toonz/sources/tnztools/brushtool.cpp
+++ b/toonz/sources/tnztools/brushtool.cpp
@@ -1616,28 +1616,40 @@ void BrushTool::mouseMove(const TPointD &pos, const TMouseEvent &e) {
       setValue(prop, value);
     }
 
-  } locals = {this};
+    void addMinMaxSeparate(TDoublePairProperty &prop, double min, double max) {
+      if (min == 0.0 && max == 0.0) return;
+      const TDoublePairProperty::Range &range = prop.getRange();
 
-  switch (e.getModifiersMask()) {
-  /*--
-   * Altキー+マウス移動で、ブラシサイズ（Min/Maxとも）を変える（CtrlやShiftでは誤操作の恐れがある）
-   * --*/
-  case TMouseEvent::ALT_KEY: {
-    // User wants to alter the minimum brush size
-    const TPointD &diff = pos - m_mousePos;
-    double add          = (fabs(diff.x) > fabs(diff.y)) ? diff.x : diff.y;
+      TDoublePairProperty::Value value = prop.getValue();
+      value.first += min;
+      value.second += max;
+      if (value.first > value.second) value.first = value.second;
+      value.first  = tcrop(value.first, range.first, range.second);
+      value.second = tcrop(value.second, range.first, range.second);
 
-    locals.addMinMax(
-        TToonzImageP(getImage(false, 1)) ? m_rasThickness : m_thickness, add);
+      setValue(prop, value);
+    }
 
-    break;
-  }
+  } locals = {this};
 
-  default:
+  // if (e.isAltPressed() && !e.isCtrlPressed()) {
+  // const TPointD &diff = pos - m_mousePos;
+  // double add = (fabs(diff.x) > fabs(diff.y)) ? diff.x : diff.y;
+
+  // locals.addMinMax(
+  //  TToonzImageP(getImage(false, 1)) ? m_rasThickness : m_thickness, add);
+  //} else
+  if (e.isCtrlPressed() && e.isAltPressed()) {
+    const TPointD &diff = pos - m_mousePos;
+    double max          = diff.x / 2;
+    double min          = diff.y / 2;
+
+    locals.addMinMaxSeparate(
+        (m_targetType & TTool::ToonzImage) ? m_rasThickness : m_thickness, min,
+        max);
+  } else {
     m_brushPos = pos;
-    break;
   }
-
   m_mousePos = pos;
   invalidate();
 
diff --git a/toonz/sources/tnztools/fullcolorbrushtool.cpp b/toonz/sources/tnztools/fullcolorbrushtool.cpp
index 5b7d27e..bfb3494 100644
--- a/toonz/sources/tnztools/fullcolorbrushtool.cpp
+++ b/toonz/sources/tnztools/fullcolorbrushtool.cpp
@@ -130,9 +130,9 @@ public:
 
 FullColorBrushTool::FullColorBrushTool(std::string name)
     : TTool(name)
-    , m_thickness("Thickness", 1, 100, 1, 5, false)
-    , m_pressure("Pressure Sensitivity", true)
-    , m_opacity("Opacity:", 0, 100, 100, 100, true)
+    , m_thickness("Size", 1, 100, 1, 5, false)
+    , m_pressure("Pressure", true)
+    , m_opacity("Opacity", 0, 100, 100, 100, true)
     , m_hardness("Hardness:", 0, 100, 100)
     , m_preset("Preset:")
     , m_styleId(0)
@@ -172,9 +172,9 @@ void FullColorBrushTool::onCanvasSizeChanged() {
 //---------------------------------------------------------------------------------------------------
 
 void FullColorBrushTool::updateTranslation() {
-  m_thickness.setQStringName(tr("Thickness"));
-  m_pressure.setQStringName(tr("Pressure Sensitivity"));
-  m_opacity.setQStringName(tr("Opacity:"));
+  m_thickness.setQStringName(tr("Size"));
+  m_pressure.setQStringName(tr("Pressure"));
+  m_opacity.setQStringName(tr("Opacity"));
   m_hardness.setQStringName(tr("Hardness:"));
   m_preset.setQStringName(tr("Preset:"));
 }
@@ -452,25 +452,36 @@ void FullColorBrushTool::mouseMove(const TPointD &pos, const TMouseEvent &e) {
       setValue(prop, value);
     }
 
-  } locals = {this};
+    void addMinMaxSeparate(TIntPairProperty &prop, double min, double max) {
+      if (min == 0.0 && max == 0.0) return;
+      const TIntPairProperty::Range &range = prop.getRange();
 
-  switch (e.getModifiersMask()) {
-  /*--
-   * Altキー+マウス移動で、ブラシサイズ（Min/Maxとも）を変える（CtrlやShiftでは誤操作の恐れがある）
-   * --*/
-  case TMouseEvent::ALT_KEY: {
-    // User wants to alter the minimum brush size
-    const TPointD &diff = pos - m_mousePos;
-    double add          = (fabs(diff.x) > fabs(diff.y)) ? diff.x : diff.y;
+      TIntPairProperty::Value value = prop.getValue();
+      value.first += min;
+      value.second += max;
+      if (value.first > value.second) value.first = value.second;
+      value.first  = tcrop<double>(value.first, range.first, range.second);
+      value.second = tcrop<double>(value.second, range.first, range.second);
+
+      setValue(prop, value);
+    }
 
-    locals.addMinMax(m_thickness, int(add));
+  } locals = {this};
 
-    break;
-  }
+  // if (e.isAltPressed() && !e.isCtrlPressed()) {
+  // const TPointD &diff = pos - m_mousePos;
+  // double add = (fabs(diff.x) > fabs(diff.y)) ? diff.x : diff.y;
 
-  default:
+  // locals.addMinMax(m_thickness, int(add));
+  //} else
+  if (e.isCtrlPressed() && e.isAltPressed()) {
+    const TPointD &diff = pos - m_mousePos;
+    double max          = diff.x / 2;
+    double min          = diff.y / 2;
+
+    locals.addMinMaxSeparate(m_thickness, int(min), int(max));
+  } else {
     m_brushPos = pos;
-    break;
   }
 
   m_mousePos = pos;
@@ -552,7 +563,8 @@ void FullColorBrushTool::setWorkAndBackupImages() {
 bool FullColorBrushTool::onPropertyChanged(std::string propertyName) {
   m_minThick = m_thickness.getValue().first;
   m_maxThick = m_thickness.getValue().second;
-  if (propertyName == "Hardness:" || propertyName == "Thickness") {
+  if (propertyName == "Hardness:" || propertyName == "Thickness" ||
+      propertyName == "Size") {
     m_brushPad = ToolUtils::getBrushPad(m_thickness.getValue().second,
                                         m_hardness.getValue() * 0.01);
     TRectD rect(m_brushPos - TPointD(m_maxThick + 2, m_maxThick + 2),
diff --git a/toonz/sources/tnztools/tooloptions.cpp b/toonz/sources/tnztools/tooloptions.cpp
index 399b876..5bb6d7a 100644
--- a/toonz/sources/tnztools/tooloptions.cpp
+++ b/toonz/sources/tnztools/tooloptions.cpp
@@ -214,7 +214,6 @@ void ToolOptionControlBuilder::visit(TDoublePairProperty *p) {
       m_tool, p, QObject::tr("Min:"), QObject::tr("Max:"), m_toolHandle);
   hLayout()->addWidget(control, 150);
   m_panel->addControl(control);
-
   if (p->getName() == "Size:" || p->getName() == "Size") {
     CommandManager *cm = CommandManager::instance();
     QAction *a;
@@ -244,8 +243,8 @@ void ToolOptionControlBuilder::visit(TIntPairProperty *p) {
       m_tool, p, QObject::tr("Min:"), QObject::tr("Max:"), m_toolHandle);
   hLayout()->addWidget(control, 100);
   m_panel->addControl(control);
-
-  if (p->getName() == "Size:") {
+  if (p->getName() == "Size:" || p->getName() == "Thickness" ||
+      p->getName() == "Size") {
     CommandManager *cm = CommandManager::instance();
     QAction *a;
     a = cm->getAction("A_IncreaseMaxBrushThickness");
@@ -278,7 +277,6 @@ void ToolOptionControlBuilder::visit(TIntProperty *p) {
     control->enableSlider(false);
     control->setFixedWidth(45);
   }
-
   hLayout()->addWidget(control, 100);
   m_panel->addControl(control);
   if (p->getName() == "Size:") {