diff --git a/pcbnew/dialogs/dialog_pns_diff_pair_dimensions.cpp b/pcbnew/dialogs/dialog_pns_diff_pair_dimensions.cpp
index 278c502d7a..dde772d0b8 100644
--- a/pcbnew/dialogs/dialog_pns_diff_pair_dimensions.cpp
+++ b/pcbnew/dialogs/dialog_pns_diff_pair_dimensions.cpp
@@ -2,7 +2,7 @@
  * KiRouter - a push-and-(sometimes-)shove PCB router
  *
  * Copyright (C) 2014-2015  CERN
- * Copyright (C) 2016 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2016-2018 KiCad Developers, see AUTHORS.txt for contributors.
  * Author: Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
  *
  * This program is free software: you can redistribute it and/or modify it
@@ -41,7 +41,8 @@ DIALOG_PNS_DIFF_PAIR_DIMENSIONS::DIALOG_PNS_DIFF_PAIR_DIMENSIONS( wxWindow* aPar
 
     updateCheckbox();
 
-    GetSizer()->SetSizeHints(this);
+    Layout();
+    GetSizer()->SetSizeHints( this );
     Centre();
 }
 
diff --git a/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.cpp b/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.cpp
index ec44c16b71..09a5ebff15 100644
--- a/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.cpp
+++ b/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.cpp
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////
-// C++ code generated with wxFormBuilder (version Nov 22 2017)
+// C++ code generated with wxFormBuilder (version Jan  2 2018)
 // http://www.wxformbuilder.org/
 //
 // PLEASE DO *NOT* EDIT THIS FILE!
@@ -44,8 +44,6 @@ DIALOG_PNS_DIFF_PAIR_DIMENSIONS_BASE::DIALOG_PNS_DIFF_PAIR_DIMENSIONS_BASE( wxWi
 	
 	m_traceGapUnit = new wxStaticText( this, wxID_ANY, _("u"), wxDefaultPosition, wxDefaultSize, 0 );
 	m_traceGapUnit->Wrap( -1 );
-	m_traceGapUnit->SetMaxSize( wxSize( 40,-1 ) );
-	
 	fgSizer1->Add( m_traceGapUnit, 0, wxALL|wxALIGN_CENTER_VERTICAL, 5 );
 	
 	m_viaGapLabel = new wxStaticText( this, wxID_ANY, _("Via gap:"), wxDefaultPosition, wxDefaultSize, 0 );
@@ -62,7 +60,6 @@ DIALOG_PNS_DIFF_PAIR_DIMENSIONS_BASE::DIALOG_PNS_DIFF_PAIR_DIMENSIONS_BASE( wxWi
 	m_viaGapUnit = new wxStaticText( this, wxID_ANY, _("u"), wxDefaultPosition, wxDefaultSize, 0 );
 	m_viaGapUnit->Wrap( -1 );
 	m_viaGapUnit->Enable( false );
-	m_viaGapUnit->SetMaxSize( wxSize( 40,-1 ) );
 	
 	fgSizer1->Add( m_viaGapUnit, 0, wxALIGN_CENTER_VERTICAL|wxALL, 5 );
 	
@@ -73,6 +70,9 @@ DIALOG_PNS_DIFF_PAIR_DIMENSIONS_BASE::DIALOG_PNS_DIFF_PAIR_DIMENSIONS_BASE( wxWi
 	m_viaTraceGapEqual->SetValue(true); 
 	bSizer7->Add( m_viaTraceGapEqual, 0, wxALL|wxEXPAND, 10 );
 	
+	
+	bSizer7->Add( 0, 0, 1, wxEXPAND, 5 );
+	
 	m_staticline1 = new wxStaticLine( this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxLI_HORIZONTAL );
 	bSizer7->Add( m_staticline1, 0, wxEXPAND, 5 );
 	
diff --git a/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.fbp b/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.fbp
index bcb7ee337b..55df80d650 100644
--- a/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.fbp
+++ b/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.fbp
@@ -575,7 +575,7 @@
                                 <property name="label">u</property>
                                 <property name="max_size"></property>
                                 <property name="maximize_button">0</property>
-                                <property name="maximum_size">40,-1</property>
+                                <property name="maximum_size">-1,-1</property>
                                 <property name="min_size"></property>
                                 <property name="minimize_button">0</property>
                                 <property name="minimum_size"></property>
@@ -832,7 +832,7 @@
                                 <property name="label">u</property>
                                 <property name="max_size"></property>
                                 <property name="maximize_button">0</property>
-                                <property name="maximum_size">40,-1</property>
+                                <property name="maximum_size">-1,-1</property>
                                 <property name="min_size"></property>
                                 <property name="minimize_button">0</property>
                                 <property name="minimum_size"></property>
@@ -970,6 +970,16 @@
                         <event name="OnUpdateUI"></event>
                     </object>
                 </object>
+                <object class="sizeritem" expanded="1">
+                    <property name="border">5</property>
+                    <property name="flag">wxEXPAND</property>
+                    <property name="proportion">1</property>
+                    <object class="spacer" expanded="1">
+                        <property name="height">0</property>
+                        <property name="permission">protected</property>
+                        <property name="width">0</property>
+                    </object>
+                </object>
                 <object class="sizeritem" expanded="1">
                     <property name="border">5</property>
                     <property name="flag">wxEXPAND</property>
diff --git a/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.h b/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.h
index 033951d4fc..60dc4a6e70 100644
--- a/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.h
+++ b/pcbnew/dialogs/dialog_pns_diff_pair_dimensions_base.h
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////
-// C++ code generated with wxFormBuilder (version Nov 22 2017)
+// C++ code generated with wxFormBuilder (version Jan  2 2018)
 // http://www.wxformbuilder.org/
 //
 // PLEASE DO *NOT* EDIT THIS FILE!