diff --git a/.gitignore b/.gitignore
index eb29d91b..8a117c39 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,6 +18,7 @@ font_gputest4.png
 font_gputest4.xcf
 manager2/
 VBO_Example.java
+math-rules-cache.zip
 
 /target/
 !/target/*.jar
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/Block.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/Block.java
index 35baae09..a942c7e2 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/Block.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/Block.java
@@ -40,8 +40,10 @@ public abstract class Block implements TreeBlock, GraphicalElement {
 	 * Used only to get inner blocks when deleting the parent block.
 	 * @return every block of every inner container, or null if empty
 	 */
-	public abstract ObjectArrayList<Block> getAllInnerBlocks();
+	public abstract ObjectArrayList<Block> getInnerBlocks();
 
+	public abstract int getInnerContainersCount();
+	
 	@Override
 	public abstract void recomputeDimensions();
 
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockChar.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockChar.java
index ca579562..1008e36a 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockChar.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockChar.java
@@ -67,8 +67,13 @@ public class BlockChar extends Block {
 	}
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		return null;
 	}
 
+	@Override
+	public int getInnerContainersCount() {
+		return 0;
+	}
+
 }
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockContainer.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockContainer.java
index 8541d545..f2be80c4 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockContainer.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockContainer.java
@@ -219,18 +219,22 @@ public class BlockContainer implements TreeContainer, GraphicalElement {
 			final int deltaCaret = caret.getRemaining();
 			removed = removed | b.delBlock(caret);
 			if (caret.getRemaining() == 0 || removed == false && deltaCaret >= 0 && caret.getRemaining() < 0) {
-				ObjectArrayList<Block> blocks = this.getBlockAt(pos - 1).get().getAllInnerBlocks();
+				ObjectArrayList<Block> blocks = this.getBlockAt(pos - 1).get().getInnerBlocks();
+				int innerContainersCount = this.getBlockAt(pos - 1).get().getInnerContainersCount();
+				if (innerContainersCount > 0) {
+					innerContainersCount--;
+				}
 				removeAt(pos - 1);
-				caret.setPosition(caret.getPosition() - deltaCaret);
 				if (blocks != null) {
 					ObjectListIterator<Block> blocksIterator = blocks.iterator();
 					int blockNum = 0;
 					while (blocksIterator.hasNext()) {
 						Block block = blocksIterator.next();
-						addBlockUnsafe(pos - 1+blockNum, block);
+						addBlockUnsafe(pos - 1 + blockNum, block);
 						blockNum++;
 					}
 				}
+				caret.setPosition(caret.getPosition() - innerContainersCount);
 				removed = true;
 			}
 		}
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockDivision.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockDivision.java
index ff368273..18e31c59 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockDivision.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockDivision.java
@@ -122,9 +122,14 @@ public class BlockDivision extends Block {
 	}
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		ObjectArrayList<Block> output = containerUp.getContent();
 		output.addAll(containerDown.getContent());
 		return output;
 	}
+
+	@Override
+	public int getInnerContainersCount() {
+		return 2;
+	}
 }
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockLogarithm.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockLogarithm.java
index b234c227..c9cd2c03 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockLogarithm.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockLogarithm.java
@@ -161,10 +161,15 @@ public class BlockLogarithm extends Block implements IParenthesis {
 	}
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		ObjectArrayList<Block> output = containerBase.getContent();
 		output.addAll(containerNumber.getContent());
 		return output;
 	}
 
+	@Override
+	public int getInnerContainersCount() {
+		return 2;
+	}
+
 }
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockParenthesis.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockParenthesis.java
index 6618de2c..01f40696 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockParenthesis.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockParenthesis.java
@@ -21,8 +21,13 @@ public class BlockParenthesis extends BlockParenthesisAbstract {
 	}
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		return getNumberContainer().getContent();
 	}
 
+	@Override
+	public int getInnerContainersCount() {
+		return 1;
+	}
+
 }
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockParenthesisAbstract.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockParenthesisAbstract.java
index 4a64695b..2f28adcd 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockParenthesisAbstract.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockParenthesisAbstract.java
@@ -117,8 +117,13 @@ public abstract class BlockParenthesisAbstract extends Block implements IParenth
 
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		return containerNumber.getContent();
 	}
+
+	@Override
+	public int getInnerContainersCount() {
+		return 1;
+	}
 	
 }
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockPower.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockPower.java
index 3632a354..f70121a5 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockPower.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockPower.java
@@ -83,7 +83,12 @@ public class BlockPower extends Block {
 	}
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		return this.containerExponent.getContent();
 	}
+
+	@Override
+	public int getInnerContainersCount() {
+		return 1;
+	}
 }
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockPower2.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockPower2.java
index 22ab21cf..3721281d 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockPower2.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockPower2.java
@@ -89,7 +89,12 @@ public class BlockPower2 extends Block {
 	}
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		return containerExponent.getContent();
 	}
+
+	@Override
+	public int getInnerContainersCount() {
+		return 1;
+	}
 }
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockSquareRoot.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockSquareRoot.java
index c87ed2e0..48a23396 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockSquareRoot.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockSquareRoot.java
@@ -98,9 +98,14 @@ public class BlockSquareRoot extends Block {
 	}
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		ObjectArrayList<Block> output = containerNumber.getContent();
 //		output.addAll();
 		return output;
 	}
+
+	@Override
+	public int getInnerContainersCount() {
+		return 1; //2
+	}
 }
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockUndefined.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockUndefined.java
index 39d529b2..e6cb92de 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockUndefined.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockUndefined.java
@@ -61,8 +61,13 @@ public class BlockUndefined extends Block {
 	}
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		return null;
 	}
 
+	@Override
+	public int getInnerContainersCount() {
+		return 0;
+	}
+
 }
diff --git a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockVariable.java b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockVariable.java
index f7c87a3a..4af7a821 100644
--- a/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockVariable.java
+++ b/core/src/main/java/it/cavallium/warppi/gui/expression/blocks/BlockVariable.java
@@ -258,7 +258,12 @@ public class BlockVariable extends Block {
 	}
 
 	@Override
-	public ObjectArrayList<Block> getAllInnerBlocks() {
+	public ObjectArrayList<Block> getInnerBlocks() {
 		return null;
 	}
+
+	@Override
+	public int getInnerContainersCount() {
+		return 0;
+	}
 }