diff --git a/samples/treectrl/treetest.cpp b/samples/treectrl/treetest.cpp
index d75bc7dd2f..1adf9954c8 100644
--- a/samples/treectrl/treetest.cpp
+++ b/samples/treectrl/treetest.cpp
@@ -291,7 +291,7 @@ MyFrame::MyFrame(const wxString& title, int x, int y, int w, int h)
     tree_menu->Append(TreeTest_DecSpacing, "Reduce spacing by 5 points\tCtrl-R");
 
     item_menu->Append(TreeTest_Dump, "&Dump item children");
-    item_menu->Append(TreeTest_Rename, "&Rename item...");
+    item_menu->Append(TreeTest_Rename, "&Rename item...\tF2");
 
     item_menu->AppendSeparator();
     item_menu->Append(TreeTest_SetBold, "Make item &bold");
diff --git a/src/generic/treectlg.cpp b/src/generic/treectlg.cpp
index da0e87c99f..67c53f0aa3 100644
--- a/src/generic/treectlg.cpp
+++ b/src/generic/treectlg.cpp
@@ -100,9 +100,10 @@ public:
 
 protected:
     void OnChar( wxKeyEvent &event );
-    void OnKeyUp( wxKeyEvent &event );
     void OnKillFocus( wxFocusEvent &event );
 
+    void IncreaseSizeForText( const wxString& text );
+
     bool AcceptChanges();
     void Finish( bool setfocus );
 
@@ -417,7 +418,6 @@ void wxTreeRenameTimer::Notify()
 
 wxBEGIN_EVENT_TABLE(wxTreeTextCtrl,wxTextCtrl)
     EVT_CHAR           (wxTreeTextCtrl::OnChar)
-    EVT_KEY_UP         (wxTreeTextCtrl::OnKeyUp)
     EVT_KILL_FOCUS     (wxTreeTextCtrl::OnKillFocus)
 wxEND_EVENT_TABLE()
 
@@ -428,6 +428,11 @@ wxTreeTextCtrl::wxTreeTextCtrl(wxGenericTreeCtrl *owner,
     m_owner = owner;
     m_aboutToFinish = false;
 
+    // Create the text hidden to show it with the correct size -- which we
+    // can't determine before creating it.
+    Hide();
+    Create(m_owner, wxID_ANY, m_startValue);
+
     wxRect rect;
     m_owner->GetBoundingRect(m_itemEdited, rect, true);
 
@@ -438,15 +443,27 @@ wxTreeTextCtrl::wxTreeTextCtrl(wxGenericTreeCtrl *owner,
     rect.x -= 5;
 #endif // platforms
 
-    (void)Create(m_owner, wxID_ANY, m_startValue,
-                 rect.GetPosition(), rect.GetSize());
+    const wxSize textSize = rect.GetSize();
+    wxSize fullSize = GetSizeFromTextSize(textSize);
+    if ( fullSize.y > textSize.y )
+    {
+        // It's ok to extend the rect to the right horizontally, which happens
+        // when we just change its size without changing its position below,
+        // but when extending it vertically, we need to keep it centered.
+        rect.y -= (fullSize.y - textSize.y + 1) / 2;
+    }
+
+    // Also check that the control fits into the parent window.
+    const int totalWidth = m_owner->GetClientSize().x;
+    if ( rect.x + fullSize.x > totalWidth )
+    {
+        fullSize.x = totalWidth - rect.x;
+    }
+
+    rect.SetSize(fullSize);
 
-    int w;
-    GetTextExtent(m_startValue, &w, nullptr);
-    const wxSize size(GetSizeFromTextSize(w));
-    rect.y += (rect.height - size.y) / 2;
-    rect.SetSize(size);
     SetSize(rect);
+    Show();
 
     SelectAll();
 }
@@ -536,28 +553,38 @@ void wxTreeTextCtrl::OnChar( wxKeyEvent &event )
             break;
 
         default:
+            if ( !m_aboutToFinish )
+            {
+                wxChar ch = event.GetUnicodeKey();
+                if ( ch != WXK_NONE )
+                {
+                    wxString value = GetValue();
+
+                    long from, to;
+                    GetSelection( &from, &to );
+                    if ( from != to )
+                    {
+                        value.Remove( from, to - from );
+                    }
+
+                    IncreaseSizeForText( value + ch );
+                }
+            }
             event.Skip();
     }
 }
 
-void wxTreeTextCtrl::OnKeyUp( wxKeyEvent &event )
+void wxTreeTextCtrl::IncreaseSizeForText( const wxString& text )
 {
-    if ( !m_aboutToFinish )
-    {
-        // auto-grow the textctrl:
-        wxSize parentSize = m_owner->GetSize();
-        wxPoint myPos = GetPosition();
-        wxSize mySize = GetSize();
-        int sx, sy;
-        GetTextExtent(GetValue() + wxT("M"), &sx, &sy);
-        if (myPos.x + sx > parentSize.x)
-            sx = parentSize.x - myPos.x;
-        if (mySize.x > sx)
-            sx = mySize.x;
+    // auto-grow the textctrl:
+    wxSize parentSize = m_owner->GetClientSize();
+    wxPoint myPos = GetPosition();
+    wxSize mySize = GetSize();
+    int sx = GetSizeFromText(text).x;
+    if (myPos.x + sx > parentSize.x)
+        sx = parentSize.x - myPos.x;
+    if (sx > mySize.x)
         SetSize(sx, wxDefaultCoord);
-    }
-
-    event.Skip();
 }
 
 void wxTreeTextCtrl::OnKillFocus( wxFocusEvent &event )
diff --git a/src/gtk/control.cpp b/src/gtk/control.cpp
index f0cb37aac2..0006ed0b66 100644
--- a/src/gtk/control.cpp
+++ b/src/gtk/control.cpp
@@ -373,6 +373,13 @@ wxSize wxControl::GTKGetEntryMargins(GtkEntry* entry) const
     GtkStyleContext* sc = gtk_widget_get_style_context(GTK_WIDGET(entry));
     gtk_style_context_get_padding(sc, gtk_style_context_get_state(sc), &border);
 #else
+    if (gtk_entry_get_has_frame(entry))
+    {
+        GtkStyle* style = GTK_WIDGET(entry)->style;
+        size.x += 2 * style->xthickness;
+        size.y += 2 * style->ythickness;
+    }
+
     // Equivalent to the GTK2 private function _gtk_entry_effective_inner_border()
 
     GtkBorder border = { 2, 2, 2, 2 };
diff --git a/src/gtk/textctrl.cpp b/src/gtk/textctrl.cpp
index ea97ffe52b..f65cfd6216 100644
--- a/src/gtk/textctrl.cpp
+++ b/src/gtk/textctrl.cpp
@@ -2133,14 +2133,13 @@ wxSize wxTextCtrl::DoGetSizeFromTextSize(int xlen, int ylen) const
 {
     wxASSERT_MSG( m_widget, wxS("GetSizeFromTextSize called before creation") );
 
-    wxSize tsize(xlen, 0);
     int cHeight = GetCharHeight();
+    wxSize tsize(xlen, cHeight);
 
     if ( IsSingleLine() )
     {
         if ( HasFlag(wxBORDER_NONE) )
         {
-            tsize.y = cHeight;
 #ifdef __WXGTK3__
             tsize.IncBy(9, 0);
 #else
@@ -2151,10 +2150,16 @@ wxSize wxTextCtrl::DoGetSizeFromTextSize(int xlen, int ylen) const
         {
             // default height
             tsize.y = GTKGetPreferredSize(m_widget).y;
-            // Add the margins we have previously set, but only the horizontal border
-            // as vertical one has been taken account at GTKGetPreferredSize().
-            // Also get other GTK+ margins.
-            tsize.IncBy( GTKGetEntryMargins(GetEntry()).x, 0);
+#ifdef __WXGTK3__
+            // Add the margins we have previously set.
+            tsize.IncBy( GTKGetEntryMargins(GetEntry()) );
+#else
+            // For GTK 2 these margins are too big, so hard code something more
+            // reasonable, this is not great but should be fine considering
+            // that it's very unlikely that GTK 2 is going to evolve, making
+            // this inappropriate.
+            tsize.IncBy(20, 0);
+#endif
         }
     }
 
@@ -2166,7 +2171,6 @@ wxSize wxTextCtrl::DoGetSizeFromTextSize(int xlen, int ylen) const
             tsize.IncBy(GTKGetPreferredSize(GTK_WIDGET(m_scrollBar[1])).x + 3, 0);
 
         // height
-        tsize.y = cHeight;
         if ( ylen <= 0 )
         {
             tsize.y = 1 + cHeight * wxMax(wxMin(GetNumberOfLines(), 10), 2);
@@ -2182,10 +2186,9 @@ wxSize wxTextCtrl::DoGetSizeFromTextSize(int xlen, int ylen) const
         }
     }
 
-    // Perhaps the user wants something different from CharHeight, or ylen
-    // is used as the height of a multiline text.
-    if ( ylen > 0 )
-        tsize.IncBy(0, ylen - cHeight);
+    // We should always use at least the specified height if it's valid.
+    if ( ylen > tsize.y )
+        tsize.y = ylen;
 
     return tsize;
 }
diff --git a/src/msw/textctrl.cpp b/src/msw/textctrl.cpp
index 2adda7d929..6f15bb6284 100644
--- a/src/msw/textctrl.cpp
+++ b/src/msw/textctrl.cpp
@@ -2555,10 +2555,9 @@ wxSize wxTextCtrl::DoGetSizeFromTextSize(int xlen, int ylen) const
         hText += EDIT_HEIGHT_FROM_CHAR_HEIGHT(cy) - cy;
     }
 
-    // Perhaps the user wants something different from CharHeight, or ylen
-    // is used as the height of a multiline text.
-    if ( ylen > 0 )
-        hText += ylen - GetCharHeight();
+    // We should always use at least the specified height if it's valid.
+    if ( ylen > hText )
+        hText = ylen;
 
     return wxSize(wText, hText);
 }