diff --git a/src/slic3r/GUI/Camera.hpp b/src/slic3r/GUI/Camera.hpp
index b9c5dfc32..6e1b539ab 100644
--- a/src/slic3r/GUI/Camera.hpp
+++ b/src/slic3r/GUI/Camera.hpp
@@ -58,7 +58,7 @@ public:
     Vec3d get_dir_up() const { return m_view_matrix.matrix().block(0, 0, 3, 3).row(1); }
     Vec3d get_dir_forward() const { return m_view_matrix.matrix().block(0, 0, 3, 3).row(2); }
 
-    Vec3d get_position() const { return m_view_matrix.matrix().block(0, 0, 3, 3).row(3); }
+    Vec3d get_position() const { return m_view_matrix.matrix().block(0, 3, 3, 1); }
 
     void apply_viewport(int x, int y, unsigned int w, unsigned int h) const;
     void apply_view_matrix() const;
diff --git a/src/slic3r/GUI/GUI_Utils.hpp b/src/slic3r/GUI/GUI_Utils.hpp
index 8cefb68d0..9577cebf4 100644
--- a/src/slic3r/GUI/GUI_Utils.hpp
+++ b/src/slic3r/GUI/GUI_Utils.hpp
@@ -65,8 +65,8 @@ public:
 		if (std::abs(m_scale_factor - scale_primary_display) > 1e-6)
 			m_normal_font = m_normal_font.Scale(m_scale_factor / scale_primary_display);
 
-        // An analog of em_unit value from GUI_App.
-        m_em_unit = std::max<size_t>(10, 10 * m_scale_factor);
+        // initialize default width_unit according to the width of the one symbol ("m") of the currently active font of this window.
+        m_em_unit = std::max<size_t>(10, this->GetTextExtent("m").x - 1);
 
 //        recalc_font();
 
diff --git a/src/slic3r/GUI/MainFrame.cpp b/src/slic3r/GUI/MainFrame.cpp
index 296776da4..41d25cff3 100644
--- a/src/slic3r/GUI/MainFrame.cpp
+++ b/src/slic3r/GUI/MainFrame.cpp
@@ -41,8 +41,6 @@ DPIFrame(NULL, wxID_ANY, "", wxDefaultPosition, wxDefaultSize, wxDEFAULT_FRAME_S
 #ifndef __WXOSX__ // Don't call SetFont under OSX to avoid name cutting in ObjectList 
     this->SetFont(this->normal_font());
 #endif
-    // initialize default width_unit according to the width of the one symbol ("m") of the currently active font of this window.
-    wxGetApp().set_em_unit(std::max<size_t>(10, GetTextExtent("m").x - 1));
 
     // Load the icon either from the exe, or from the ico file.
 #if _WIN32
@@ -315,8 +313,6 @@ void MainFrame::on_dpi_changed(const wxRect &suggested_rect)
 {
     wxGetApp().update_fonts();
     this->SetFont(this->normal_font());
-    // initialize default width_unit according to the width of the one symbol ("m") of the currently active font of this window.
-    wxGetApp().set_em_unit(std::max<size_t>(10, GetTextExtent("m").x - 1));
 
     /* Load default preset bitmaps before a tabpanel initialization,
      * but after filling of an em_unit value
diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index d5b8ee4c1..b6bdb7a4b 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -178,7 +178,7 @@ void Tab::create_preset_tab()
     // Sizer with buttons for mode changing
     m_mode_sizer = new ModeSizer(panel);
 
-    const float scale_factor = wxGetApp().em_unit()*0.1;// GetContentScaleFactor();
+    const float scale_factor = /*wxGetApp().*/em_unit(this)*0.1;// GetContentScaleFactor();
 	m_hsizer = new wxBoxSizer(wxHORIZONTAL);
 	sizer->Add(m_hsizer, 0, wxEXPAND | wxBOTTOM, 3);
 	m_hsizer->Add(m_presets_choice, 0, wxLEFT | wxRIGHT | wxTOP | wxALIGN_CENTER_VERTICAL, 3);
@@ -212,7 +212,8 @@ void Tab::create_preset_tab()
     m_treectrl = new wxTreeCtrl(panel, wxID_ANY, wxDefaultPosition, wxSize(20 * m_em_unit, -1),
 		wxTR_NO_BUTTONS | wxTR_HIDE_ROOT | wxTR_SINGLE | wxTR_NO_LINES | wxBORDER_SUNKEN | wxWANTS_CHARS);
 	m_left_sizer->Add(m_treectrl, 1, wxEXPAND);
-    m_icons = new wxImageList(int(16 * scale_factor), int(16 * scale_factor), true, 1);
+    const int img_sz = int(16 * scale_factor + 0.5f);
+    m_icons = new wxImageList(img_sz, img_sz, true, 1);
 	// Index of the last icon inserted into $self->{icons}.
 	m_icon_count = -1;
 	m_treectrl->AssignImageList(m_icons);
diff --git a/src/slic3r/GUI/wxExtensions.cpp b/src/slic3r/GUI/wxExtensions.cpp
index 24fe778c9..0e89a72f2 100644
--- a/src/slic3r/GUI/wxExtensions.cpp
+++ b/src/slic3r/GUI/wxExtensions.cpp
@@ -1871,9 +1871,9 @@ void DoubleSlider::draw_action_icon(wxDC& dc, const wxPoint pt_beg, const wxPoin
 {
     const int tick = m_selection == ssLower ? m_lower_value : m_higher_value;
 
-    wxBitmap& icon = m_is_action_icon_focesed ? m_bmp_add_tick_off.bmp() : m_bmp_add_tick_on.bmp();
+    wxBitmap* icon = m_is_action_icon_focesed ? &m_bmp_add_tick_off.bmp() : &m_bmp_add_tick_on.bmp();
     if (m_ticks.find(tick) != m_ticks.end())
-        icon = m_is_action_icon_focesed ? m_bmp_del_tick_off.bmp() : m_bmp_del_tick_on.bmp();
+        icon = m_is_action_icon_focesed ? &m_bmp_del_tick_off.bmp() : &m_bmp_del_tick_on.bmp();
 
     wxCoord x_draw, y_draw;
     is_horizontal() ? x_draw = pt_beg.x - 0.5*m_tick_icon_dim : y_draw = pt_beg.y - 0.5*m_tick_icon_dim;
@@ -1882,7 +1882,7 @@ void DoubleSlider::draw_action_icon(wxDC& dc, const wxPoint pt_beg, const wxPoin
     else
         is_horizontal() ? y_draw = pt_beg.y - m_tick_icon_dim-2 : x_draw = pt_end.x + 3;
 
-    dc.DrawBitmap(icon, x_draw, y_draw);
+    dc.DrawBitmap(*icon, x_draw, y_draw);
 
     //update rect of the tick action icon
     m_rect_tick_action = wxRect(x_draw, y_draw, m_tick_icon_dim, m_tick_icon_dim);