diff --git a/src/app/doc_exporter.cpp b/src/app/doc_exporter.cpp
index 57e79bdcf..9eb62541a 100644
--- a/src/app/doc_exporter.cpp
+++ b/src/app/doc_exporter.cpp
@@ -1185,13 +1185,18 @@ Doc* DocExporter::createEmptyTexture(const Samples& samples,
   int maxColors = 256;
   gfx::ColorSpaceRef colorSpace;
   color_t transparentColor = 0;
-  bool ui = false;
-#ifdef ENABLE_UI
-  if (App::instance()->isGui())
-    ui = true;
-#endif
+
+  // We generate a palette for file formats that support a color
+  // palette inside, or if the UI/preview is available/required.
+  //
+  // As a side note, here we cannot use a possible
+  // ctx->isUIAvailable() (instead of App::instance()->isGui())
+  // because when the sprite sheet is generated from the UI, a
+  // temporal non-UI context is created in a background thread.
+  const bool paletteRequiredByUIPreview = App::instance()->isGui();
   const bool textureSupportsPalette =
-    format_supports_palette(m_textureFilename) || ui;
+    format_supports_palette(m_textureFilename) ||
+    paletteRequiredByUIPreview;
 
   for (const auto& sample : samples) {
     if (token.canceled())