Fix clipped combobox entry in board editor text box dialog.

The layer combobox color swatch was clipped when the combobox was
closed when the dialog was launched.  Setting the minimum width
resolved the issue.  This may have been a GTK only issue.

pcbnew/dialogs/dialog_textbox_properties_base.cpp

@@ -66,7 +66,7 @@ DIALOG_TEXTBOX_PROPERTIES_BASE::DIALOG_TEXTBOX_PROPERTIES_BASE( wxWindow* parent
 	bMainSizer->Add( m_MultiLineSizer, 20, wxEXPAND|wxALL, 10 );
 
 	wxGridBagSizer* gbSizer1;
-	gbSizer1 = new wxGridBagSizer( 2, 3 );
+	gbSizer1 = new wxGridBagSizer( 3, 3 );
 	gbSizer1->SetFlexibleDirection( wxBOTH );
 	gbSizer1->SetNonFlexibleGrowMode( wxFLEX_GROWMODE_SPECIFIED );
 	gbSizer1->SetEmptyCellSize( wxSize( -1,8 ) );
@@ -79,6 +79,8 @@ DIALOG_TEXTBOX_PROPERTIES_BASE::DIALOG_TEXTBOX_PROPERTIES_BASE( wxWindow* parent
 	gbSizer1->Add( m_LayerLabel, wxGBPosition( 1, 0 ), wxGBSpan( 1, 1 ), wxALIGN_CENTER_VERTICAL|wxTOP|wxBOTTOM|wxLEFT, 5 );
 
 	m_LayerSelectionCtrl = new PCB_LAYER_BOX_SELECTOR( this, wxID_ANY, wxEmptyString, wxDefaultPosition, wxDefaultSize, 0, NULL, 0 );
+	m_LayerSelectionCtrl->SetMinSize( wxSize( 175,-1 ) );
+
 	gbSizer1->Add( m_LayerSelectionCtrl, wxGBPosition( 1, 1 ), wxGBSpan( 1, 2 ), wxALIGN_CENTER_VERTICAL|wxEXPAND, 5 );
 
 	m_fontLabel = new wxStaticText( this, wxID_ANY, _("Font:"), wxDefaultPosition, wxDefaultSize, 0 );

pcbnew/dialogs/dialog_textbox_properties_base.fbp

@@ -216,7 +216,7 @@
                         <property name="name">gbSizer1</property>
                         <property name="non_flexible_grow_mode">wxFLEX_GROWMODE_SPECIFIED</property>
                         <property name="permission">none</property>
-                        <property name="vgap">2</property>
+                        <property name="vgap">3</property>
                         <object class="gbsizeritem" expanded="1">
                             <property name="border">5</property>
                             <property name="colspan">3</property>
@@ -389,7 +389,7 @@
                                 <property name="maximum_size"></property>
                                 <property name="min_size"></property>
                                 <property name="minimize_button">0</property>
-                                <property name="minimum_size"></property>
+                                <property name="minimum_size">175,-1</property>
                                 <property name="moveable">1</property>
                                 <property name="name">m_LayerSelectionCtrl</property>
                                 <property name="pane_border">1</property>