message: fix occasional crash on resize
  [ci skip]
diff: @@ -484,10 +484,13 @@ namespace ospray {
  frameBufferMode = ImGui3DWidget::FRAMEBUFFER_FLOAT;
  break;
  }
  +
  fbSize = mappedFB.size();
  - ucharFB = (uint32_t *)mappedFB.data();
  + if (fbSize == renderSize) {
  + ucharFB = (uint32_t *)mappedFB.data();
  ImGui3DWidget::display();
  + }
  if (saveScreenshot) {
  std::string filename("ospexampleviewer");
  @@ -561,7 +564,7 @@ namespace ospray {
  &cancelFrameOnInteraction));
  if (ImGui::DragFloat("Render Resolution Scale", &renderResolutionScale,
  - .01f, 0.01f, 1.f)) {
  + .01f, 0.01f, 4.f)) {
  reshape(windowSize);
  }
  