diff --git a/src/stc/PlatWX.cpp b/src/stc/PlatWX.cpp
index a01287d4c3..84012f84e3 100644
--- a/src/stc/PlatWX.cpp
+++ b/src/stc/PlatWX.cpp
@@ -2647,6 +2647,7 @@ public:
 
     // Setters
     void SetContainerBorderSize(int);
+    void SetMaxListBoxWidth(int);
 
     // ListBoxImpl implementation
     virtual void SetListBoxFont(Font &font);
@@ -2698,6 +2699,7 @@ protected:
     int m_textHeight;
     int m_itemHeight;
     int m_textTopGap;
+    int m_maxBoxWidth;  // 0 means no max width
 
     // These drawing parameters are set internally and can be changed if needed
     // to better match the appearance of a list box on a specific platform.
@@ -2711,7 +2713,7 @@ wxSTCListBox::wxSTCListBox(wxWindow* parent, wxSTCListBoxVisualData* v, int ht)
               m_visualData(v), m_maxStrWidth(0), m_currentRow(wxNOT_FOUND),
               m_doubleClickAction(NULL), m_doubleClickActionData(NULL),
               m_aveCharWidth(8), m_textHeight(ht), m_itemHeight(ht),
-              m_textTopGap(0)
+              m_textTopGap(0), m_maxBoxWidth(350)
 {
     wxVListBox::Create(parent, wxID_ANY, wxDefaultPosition, wxDefaultSize,
                        wxBORDER_NONE, "AutoCompListBox");
@@ -2757,6 +2759,11 @@ void wxSTCListBox::SetContainerBorderSize(int s)
     m_borderSize = s;
 }
 
+void wxSTCListBox::SetMaxListBoxWidth(int maxWidth)
+{
+    m_maxBoxWidth = maxWidth;
+}
+
 void wxSTCListBox::SetListBoxFont(Font &font)
 {
     SetFont(*((wxFont*)font.GetID()));
@@ -2776,10 +2783,14 @@ PRectangle wxSTCListBox::GetDesiredRect() const
     int maxh ;
 
     // give it a default if there are no lines, and/or add a bit more
-    if (maxw == 0) maxw = 100;
+    if ( maxw == 0 )
+        maxw = 100;
+
     maxw += TextBoxFromClientEdge() + m_textBoxToTextGap + m_aveCharWidth * 3;
-    if (maxw > 350)
-        maxw = 350;
+
+    // m_maxBoxWidth == 0 or negative means no maximum
+    if ( ( m_maxBoxWidth > 0 ) && ( maxw > m_maxBoxWidth ) )
+        maxw = m_maxBoxWidth;
 
     // estimate a desired height
     const int count = Length();
@@ -3271,7 +3282,7 @@ void wxSTCListBoxWin::OnPaint(wxPaintEvent& WXUNUSED(evt))
 //----------------------------------------------------------------------
 
 ListBoxImpl::ListBoxImpl()
-            :m_listBox(NULL), m_visualData(new wxSTCListBoxVisualData(5))
+            :m_listBox(NULL), m_visualData(new wxSTCListBoxVisualData(5)), m_listBoxWidth(-1)
 {
 }
 
@@ -3290,6 +3301,19 @@ void ListBoxImpl::Create(Window &parent, int WXUNUSED(ctrlID),
                          bool WXUNUSED(unicodeMode_), int technology_) {
     wid = new wxSTCListBoxWin(GETWIN(parent.GetID()), &m_listBox, m_visualData,
                               lineHeight_, technology_);
+
+    if ( m_listBoxWidth >= 0 )
+        m_listBox->SetMaxListBoxWidth(m_listBoxWidth);
+}
+
+
+void ListBoxImpl::SetMaxListBoxWidth(int width) {
+    // Store the setting for future list box creations
+    m_listBoxWidth = width;
+
+    // Update the listbox if it currently exists, but allow this to be called before it is created
+    if ( m_listBox )
+        m_listBox->SetMaxListBoxWidth(m_listBoxWidth);
 }
 
 
diff --git a/src/stc/PlatWX.h b/src/stc/PlatWX.h
index bdaf7fef4b..c613607fb4 100644
--- a/src/stc/PlatWX.h
+++ b/src/stc/PlatWX.h
@@ -23,6 +23,10 @@ private:
     wxSTCListBox*           m_listBox;
     wxSTCListBoxVisualData* m_visualData;
 
+    // Allow the implementation to control the width of the underlying listbox.
+    // If this is negative, then the underlying listbox retains control over the max width.
+    int                     m_listBoxWidth;
+
 public:
     ListBoxImpl();
     ~ListBoxImpl();
@@ -30,6 +34,7 @@ public:
 
     virtual void SetFont(Font &font) wxOVERRIDE;
     virtual void Create(Window &parent, int ctrlID, Point location_, int lineHeight_, bool unicodeMode_, int technology_) wxOVERRIDE;
+            void SetMaxListBoxWidth(int width);
     virtual void SetAverageCharWidth(int width) wxOVERRIDE;
     virtual void SetVisibleRows(int rows) wxOVERRIDE;
     virtual int GetVisibleRows() const wxOVERRIDE;
diff --git a/src/stc/ScintillaWX.cpp b/src/stc/ScintillaWX.cpp
index 5537bebb05..ef06279ebd 100644
--- a/src/stc/ScintillaWX.cpp
+++ b/src/stc/ScintillaWX.cpp
@@ -292,8 +292,11 @@ void ScintillaWX::Initialise() {
     kmap.AssignCmdKey(SCK_DOWN, SCI_CTRL, SCI_DOCUMENTEND);
 #endif // __WXMAC__
 
-    static_cast<ListBoxImpl*>(ac.lb)->SetListInfo(&listType, &(ac.posStart),
-                                                  &(ac.startLen));
+    ListBoxImpl* autoCompleteLB = static_cast<ListBoxImpl*>( ac.lb );
+
+    // Let the Scintilla autocomplete engine determine the max size for the listbox
+    autoCompleteLB->SetMaxListBoxWidth( 0 );
+    autoCompleteLB->SetListInfo( &listType, &(ac.posStart), &(ac.startLen) );
 }