diff --git a/interface/wx/aui/auibar.h b/interface/wx/aui/auibar.h
index 12d9255be5..3bfa1763a4 100644
--- a/interface/wx/aui/auibar.h
+++ b/interface/wx/aui/auibar.h
@@ -47,7 +47,10 @@ enum wxAuiToolBarStyle
     wxAUI_TB_VERTICAL      = 1 << 5,
 
     /**
-      Shows the text and the icons alongside, not vertically stacked. This style must be used with wxAUI_TB_TEXT
+      Shows the text and the icons alongside, not vertically stacked.
+
+      This style must be used with wxAUI_TB_TEXT and can't be used with
+      wxAUI_TB_VERTICAL.
     */
     wxAUI_TB_HORZ_LAYOUT   = 1 << 6,
 
@@ -755,6 +758,9 @@ public:
         whereas by default it can be horizontal or vertical and
         be docked anywhere.
     @style{wxAUI_TB_HORZ_LAYOUT}
+        For horizontal toolbars, show the text and the icons alongside,
+        not vertically stacked. This style must be used with wxAUI_TB_TEXT
+        and can't be used with wxAUI_TB_VERTICAL.
     @style{wxAUI_TB_HORIZONTAL}
         Analogous to wxAUI_TB_VERTICAL, but forces the toolbar
         to be horizontal.
diff --git a/src/aui/auibar.cpp b/src/aui/auibar.cpp
index c3dab7ddd8..b0b00364d7 100644
--- a/src/aui/auibar.cpp
+++ b/src/aui/auibar.cpp
@@ -909,6 +909,16 @@ bool wxAuiToolBar::Create(wxWindow* parent,
     SetFont(*wxNORMAL_FONT);
     SetArtFlags();
     SetExtraStyle(wxWS_EX_PROCESS_IDLE);
+
+    if ( style & wxAUI_TB_VERTICAL )
+    {
+        wxASSERT_MSG
+        (
+         !(style & wxAUI_TB_HORZ_LAYOUT),
+         "Horizontal layout style can't be used with vertical toolbars"
+        );
+    }
+
     if (style & wxAUI_TB_HORZ_LAYOUT)
         SetToolTextOrientation(wxAUI_TBTOOL_TEXT_RIGHT);
     SetBackgroundStyle(wxBG_STYLE_PAINT);