FIX:fixed crashed when starting Studio on secondary display

Change-Id: I0392607479a25b5e2b2704f5569d6b8b94ba7e3d

src/slic3r/GUI/GLCanvas3D.cpp

@@ -5906,8 +5906,16 @@ void GLCanvas3D::_check_and_update_toolbar_icon_scale()
     float noitems_width = top_tb_width - size * items_cnt; // width of separators and borders in top toolbars
 
     // calculate scale needed for items in all top toolbars
+#ifdef __WINDOWS__
+    cnv_size.set_width(cnv_size.get_width() + m_separator_toolbar.get_width() + collapse_toolbar_width);
+#endif
     float new_h_scale = (cnv_size.get_width() - noitems_width) / (items_cnt * GLToolbar::Default_Icons_Size);
 
+    //for protect
+    if (new_h_scale <= 0) {
+        new_h_scale = 1;
+    }
+
     //use the same value as horizon
     float new_v_scale = new_h_scale;
 #else