diff --git a/src/app/app.cpp b/src/app/app.cpp
index 2657df729..aa5c44796 100644
--- a/src/app/app.cpp
+++ b/src/app/app.cpp
@@ -17,6 +17,7 @@
 #include "app/cli/cli_processor.h"
 #include "app/cli/default_cli_delegate.h"
 #include "app/cli/preview_cli_delegate.h"
+#include "app/color_spaces.h"
 #include "app/color_utils.h"
 #include "app/commands/commands.h"
 #include "app/console.h"
@@ -59,11 +60,11 @@
 #include "base/split_string.h"
 #include "doc/sprite.h"
 #include "fmt/format.h"
-#include "render/render.h"
 #include "os/display.h"
 #include "os/error.h"
 #include "os/surface.h"
 #include "os/system.h"
+#include "render/render.h"
 #include "ui/intern.h"
 #include "ui/ui.h"
 
@@ -104,6 +105,9 @@ class App::CoreModules {
 public:
   ConfigModule m_configModule;
   Preferences m_preferences;
+  CoreModules() {
+    initialize_color_spaces();
+  }
 };
 
 class App::LoadLanguage {
diff --git a/src/app/color_spaces.cpp b/src/app/color_spaces.cpp
index e132dfc64..46e4cccd2 100644
--- a/src/app/color_spaces.cpp
+++ b/src/app/color_spaces.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018  Igara Studio S.A.
+// Copyright (C) 2018-2019  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -19,6 +19,20 @@
 
 namespace app {
 
+// We use this variable to avoid accessing Preferences::instance()
+// from background threads when a color conversion between color
+// spaces must be done.
+static bool g_manage = false;
+
+void initialize_color_spaces()
+{
+  g_manage = Preferences::instance().color.manage();
+  Preferences::instance().color.manage.AfterChange.connect(
+    [](bool manage){
+      g_manage = manage;
+    });
+}
+
 os::ColorSpacePtr get_screen_color_space()
 {
   return os::instance()->defaultDisplay()->colorSpace();
@@ -56,7 +70,7 @@ gfx::ColorSpacePtr get_working_rgb_space_from_preferences()
 
 ConvertCS::ConvertCS()
 {
-  if (Preferences::instance().color.manage()) {
+  if (g_manage) {
     auto srcCS = get_current_color_space();
     auto dstCS = get_screen_color_space();
     if (srcCS && dstCS)
@@ -67,7 +81,7 @@ ConvertCS::ConvertCS()
 ConvertCS::ConvertCS(const os::ColorSpacePtr& srcCS,
                      const os::ColorSpacePtr& dstCS)
 {
-  if (Preferences::instance().color.manage()) {
+  if (g_manage) {
     m_conversion = os::instance()->convertBetweenColorSpace(srcCS, dstCS);
   }
 }
diff --git a/src/app/color_spaces.h b/src/app/color_spaces.h
index 2a1cdabc2..cebdf2684 100644
--- a/src/app/color_spaces.h
+++ b/src/app/color_spaces.h
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018  Igara Studio S.A.
+// Copyright (C) 2018-2019  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -20,6 +20,8 @@ namespace doc {
 
 namespace app {
 
+  void initialize_color_spaces();
+
   os::ColorSpacePtr get_screen_color_space();
 
   // Returns the color space of the current document.
diff --git a/src/ui/system.cpp b/src/ui/system.cpp
index 982035c1a..6caec99ee 100644
--- a/src/ui/system.cpp
+++ b/src/ui/system.cpp
@@ -362,7 +362,8 @@ void execute_from_ui_thread(std::function<void()>&& f)
 
 bool is_ui_thread()
 {
-  return (main_gui_thread == base::this_thread::native_handle());
+  return (!main_gui_thread ||
+          main_gui_thread == base::this_thread::native_handle());
 }
 
 #ifdef _DEBUG