diff --git a/include/wx/generic/grid.h b/include/wx/generic/grid.h
index fcb2f8b4b8..96a3844f6b 100644
--- a/include/wx/generic/grid.h
+++ b/include/wx/generic/grid.h
@@ -823,11 +823,12 @@ public:
                m_leftCol <= cell.GetCol() && cell.GetCol() <= m_rightCol;
     }
 
-    // Whether the blocks contain each other.
-    // returns 1, if this block contains the other,
-    //        -1, if the other block contains this one,
-    //         0, otherwise
-    int ContainBlock(const wxGridBlockCoords& other) const;
+    // Return whether this blocks fully contains another one.
+    bool ContainsBlock(const wxGridBlockCoords& other) const
+    {
+        return m_topRow <= other.m_topRow && other.m_bottomRow <= m_bottomRow &&
+               m_leftCol <= other.m_leftCol && other.m_rightCol <= m_rightCol;
+    }
 
     // Calculates the result blocks by subtracting the other block from this
     // block. splitOrientation can be wxVERTICAL or wxHORIZONTAL.
diff --git a/interface/wx/grid.h b/interface/wx/grid.h
index 6e263abb58..6122f6b3fa 100644
--- a/interface/wx/grid.h
+++ b/interface/wx/grid.h
@@ -1924,14 +1924,12 @@ public:
     bool ContainsCell(const wxGridCellCoords& cell) const;
 
     /**
-        Whether the blocks contain each other.
+        Check whether this block contains another one.
 
         @return
-            1, if this block contains the other,
-            -1, if the other block contains this one,
-            0, otherwise.
+            @true if @a other is entirely contained within this block.
      */
-    int ContainBlock(const wxGridBlockCoords& other) const;
+    int ContainsBlock(const wxGridBlockCoords& other) const;
 
     /**
         Calculates the result blocks by subtracting the other block from this
diff --git a/src/generic/grid.cpp b/src/generic/grid.cpp
index ed5a8bc3d3..70ee786943 100644
--- a/src/generic/grid.cpp
+++ b/src/generic/grid.cpp
@@ -1140,21 +1140,6 @@ const wxGridCornerHeaderRenderer& wxGridCellAttrProvider::GetCornerRenderer()
 // wxGridBlockCoords
 // ----------------------------------------------------------------------------
 
-int wxGridBlockCoords::ContainBlock(const wxGridBlockCoords& other) const
-{
-// returns 1, if this block contains the other,
-//        -1, if the other block contains this one,
-//         0, otherwise
-    if ( m_topRow <= other.m_topRow && other.m_bottomRow <= m_bottomRow &&
-         m_leftCol <= other.m_leftCol && other.m_rightCol <= m_rightCol )
-        return 1;
-    else if ( other.m_topRow <= m_topRow && m_bottomRow <= other.m_bottomRow &&
-              other.m_leftCol <= m_leftCol && m_rightCol <= other.m_rightCol )
-        return -1;
-
-    return 0;
-}
-
 wxGridBlockDiffResult
 wxGridBlockCoords::Difference(const wxGridBlockCoords& other,
                               int splitOrientation) const
diff --git a/src/generic/gridsel.cpp b/src/generic/gridsel.cpp
index 62ea7312d7..6fcd64140f 100644
--- a/src/generic/gridsel.cpp
+++ b/src/generic/gridsel.cpp
@@ -741,19 +741,14 @@ void wxGridSelection::MergeOrAddBlock(wxVectorGridBlockCoords& blocks,
     {
         const wxGridBlockCoords& block = blocks[n];
 
-        switch ( block.ContainBlock(newBlock) )
+        if ( block.ContainsBlock(newBlock) )
+            return;
+
+        if ( newBlock.ContainsBlock(block) )
         {
-            case 1:
-                return;
-
-            case -1:
-                blocks.erase(blocks.begin() + n);
-                n--;
-                count--;
-                break;
-
-            default:
-                break;
+            blocks.erase(blocks.begin() + n);
+            n--;
+            count--;
         }
     }
 
diff --git a/tests/controls/gridtest.cpp b/tests/controls/gridtest.cpp
index f1749634c9..708f42cd18 100644
--- a/tests/controls/gridtest.cpp
+++ b/tests/controls/gridtest.cpp
@@ -1337,17 +1337,19 @@ TEST_CASE("GridBlockCoords::ContainsCell", "[grid]")
     CHECK(!wxGridBlockCoords(1, 1, 3, 3).ContainsCell(wxGridCellCoords(5, 5)));
 }
 
-TEST_CASE("GridBlockCoords::ContainBlock", "[grid]")
+TEST_CASE("GridBlockCoords::ContainsBlock", "[grid]")
 {
     wxGridBlockCoords block1(1, 1, 5, 5);
     wxGridBlockCoords block2(1, 1, 3, 3);
     wxGridBlockCoords block3(2, 2, 7, 7);
     wxGridBlockCoords block4(10, 10, 12, 12);
 
-    CHECK(block1.ContainBlock(block2) == 1);
-    CHECK(block2.ContainBlock(block1) == -1);
-    CHECK(block1.ContainBlock(block3) == 0);
-    CHECK(block1.ContainBlock(block4) == 0);
+    CHECK( block1.ContainsBlock(block2));
+    CHECK(!block2.ContainsBlock(block1));
+    CHECK(!block1.ContainsBlock(block3));
+    CHECK(!block1.ContainsBlock(block4));
+    CHECK(!block3.ContainsBlock(block1));
+    CHECK(!block4.ContainsBlock(block1));
 }
 
 TEST_CASE("GridBlockCoords::Difference", "[grid]")