diff --git a/NCPCompat/src/main/java/fr/neatmonster/nocheatplus/utilities/InventoryUtil.java b/NCPCompat/src/main/java/fr/neatmonster/nocheatplus/utilities/InventoryUtil.java
new file mode 100644
index 00000000..9a764048
--- /dev/null
+++ b/NCPCompat/src/main/java/fr/neatmonster/nocheatplus/utilities/InventoryUtil.java
@@ -0,0 +1,61 @@
+package fr.neatmonster.nocheatplus.utilities;
+
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryView;
+import org.bukkit.inventory.ItemStack;
+
+public class InventoryUtil {
+	
+	/**
+	 * Does not account for special slots like armor.
+	 * @param inventory
+	 * @return
+	 */
+	public static int getFreeSlots(final Inventory inventory){
+		final ItemStack[] contents = inventory.getContents();
+		int count = 0;
+		for (int i = 0; i < contents.length; i++){
+			final ItemStack stack = contents[i];
+			if (stack == null || stack.getTypeId() == 0){
+				count ++;
+			}
+		}
+		return count;
+	}
+
+	/**
+	 * Count slots with type-id and data (enchantments are ignored at present).
+	 * @param inventory
+	 * @param reference
+	 * @return
+	 */
+	public static int getStackCount(final Inventory inventory, final ItemStack reference) {
+		if (inventory == null) return 0;
+		if (reference == null) return getFreeSlots(inventory);
+		final int id = reference.getTypeId();
+		final int durability = reference.getDurability();
+		final ItemStack[] contents = inventory.getContents();
+		int count = 0;
+		for (int i = 0; i < contents.length; i++){
+			final ItemStack stack = contents[i];
+			if (stack == null){
+				continue;
+			}
+			else if (stack.getTypeId() == id && stack.getDurability() == durability){
+				count ++;
+			}
+		}
+		return count;
+	}
+
+	/**
+	 * Sum of bottom + top inventory slots with item type / data, see: getStackCount(Inventory, reference).
+	 * @param view
+	 * @param reference
+	 * @return
+	 */
+	public static int getStackCount(final InventoryView view, final ItemStack reference) {
+		return getStackCount(view.getBottomInventory(), reference) + getStackCount(view.getTopInventory(), reference);
+	}
+
+}
diff --git a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/FastClick.java b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/FastClick.java
index c30df2c5..91fa45ea 100644
--- a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/FastClick.java
+++ b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/FastClick.java
@@ -2,12 +2,14 @@ package fr.neatmonster.nocheatplus.checks.inventory;
 
 import org.bukkit.Material;
 import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryView;
 import org.bukkit.inventory.ItemStack;
 
 import fr.neatmonster.nocheatplus.checks.Check;
 import fr.neatmonster.nocheatplus.checks.CheckType;
 import fr.neatmonster.nocheatplus.checks.ViolationData;
 import fr.neatmonster.nocheatplus.permissions.Permissions;
+import fr.neatmonster.nocheatplus.utilities.InventoryUtil;
 import fr.neatmonster.nocheatplus.utilities.TickTask;
 
 /*
@@ -81,32 +83,34 @@ public class FastClick extends Check {
 //        return cancel;
 //    }
     
-    public boolean check(final Player player, final long now, final int slot, final ItemStack cursor, final ItemStack clicked, final InventoryData data, final InventoryConfig cc) {
+    public boolean check(final Player player, final long now, final InventoryView view, final int slot, final ItemStack cursor, final ItemStack clicked, final boolean isShiftClick, final InventoryData data, final InventoryConfig cc) {
     	// Take time once.
     	
     	final float amount;
     	
     	if (cursor != null && cc.fastClickTweaks1_5){
-    		final Material mat = cursor.getType();
-    		final int size = cursor.getAmount();
-    		if (mat != data.fastClickLastMat || mat == Material.AIR || size != data.fastClickLastAmount || clicked == null){
+    		final Material cursorMat = cursor.getType();
+    		final int cursorAmount = Math.max(1, cursor.getAmount());
+    		final Material clickedMat = clicked == null ? Material.AIR : clicked.getType();
+    		if (cursorMat != data.fastClickLastCursor && (!isShiftClick || clicked == null || clicked.getType() != data.fastClickLastClicked) || cursorMat == Material.AIR || cursorAmount != data.fastClickLastCursorAmount){
     			amount = 1f;
     		}
     		else{
-    			final Material cMat = clicked.getType();
-    			if (cMat == Material.AIR || cMat == mat){
-    				amount = Math.min(cc.fastClickNormalLimit , cc.fastClickShortTermLimit) / (float) size * 0.75f;
+    			if (clickedMat == Material.AIR || clickedMat == cursorMat || isShiftClick && clickedMat == data.fastClickLastClicked ){
+    				amount = Math.min(cc.fastClickNormalLimit , cc.fastClickShortTermLimit) / (float) (isShiftClick && clickedMat != Material.AIR ? (1.0 + Math.max(cursorAmount, InventoryUtil.getStackCount(view, clicked))) : cursorAmount)  * 0.75f;
     			}
     			else{
     				amount = 1f;
     			}
     		}
-        	data.fastClickLastMat = mat;
-        	data.fastClickLastAmount = size;
+        	data.fastClickLastCursor = cursorMat;
+        	data.fastClickLastClicked = clickedMat;
+        	data.fastClickLastCursorAmount = cursorAmount;
     	}
     	else{
-        	data.fastClickLastMat = null;
-        	data.fastClickLastAmount = 0;
+        	data.fastClickLastCursor = null;
+        	data.fastClickLastClicked = null;
+        	data.fastClickLastCursorAmount = 0;
     		amount = 1f;
     	}
         
@@ -137,7 +141,7 @@ public class FastClick extends Check {
         }
         
         if (cc.debug && player.hasPermission(Permissions.ADMINISTRATION_DEBUG)){
-        	player.sendMessage("FastClick: " + data.fastClickFreq.bucketScore(0) + " / " + data.fastClickFreq.score(1f));
+        	player.sendMessage("FastClick: " + data.fastClickFreq.bucketScore(0) + " | " + data.fastClickFreq.score(1f) + " | cursor=" + cursor + " | clicked=" + clicked);
         }
         
         return cancel;
diff --git a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/InventoryData.java b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/InventoryData.java
index a9e50d7b..df2a087e 100644
--- a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/InventoryData.java
+++ b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/InventoryData.java
@@ -84,8 +84,9 @@ public class InventoryData extends ACheckData {
     // Data of the fast click check.
 //    public boolean  fastClickLastCancelled;
     public final ActionFrequency fastClickFreq = new ActionFrequency(5, 200L);
-	public Material fastClickLastMat = null;
-	public int fastClickLastAmount = 0;
+	public Material fastClickLastCursor = null;
+	public Material fastClickLastClicked = null;
+	public int fastClickLastCursorAmount = 0;
 
     // Data of the instant bow check.
     public long     instantBowInteract;
diff --git a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/InventoryListener.java b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/InventoryListener.java
index ceddd498..33735844 100644
--- a/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/InventoryListener.java
+++ b/NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/checks/inventory/InventoryListener.java
@@ -186,7 +186,7 @@ public class InventoryListener  extends CheckListener {
             if (fastClick.isEnabled(player)){
                 final InventoryConfig cc = InventoryConfig.getConfig(player);
                 if (player.getGameMode() != GameMode.CREATIVE || !cc.fastClickSpareCreative){
-                    if (fastClick.check(player, now, slot, cursor, clicked, data, cc)){
+                    if (fastClick.check(player, now, event.getView(), slot, cursor, clicked, event.isShiftClick(), data, cc)){
                         // The check requested the event to be cancelled.
                         event.setCancelled(true);
                     }