diff --git a/xo-imgui/example/ex4a/VulkanApp.cpp b/xo-imgui/example/ex4a/VulkanApp.cpp
index 52e69d4a..c3b7d59a 100644
--- a/xo-imgui/example/ex4a/VulkanApp.cpp
+++ b/xo-imgui/example/ex4a/VulkanApp.cpp
@@ -322,4 +322,20 @@ MinimalImGuiVulkan::create_command_pool()
     }
 }
 
+void
+MinimalImGuiVulkan::create_command_buffers()
+{
+    command_buffers_.resize(MAX_FRAMES_IN_FLIGHT);
+
+    VkCommandBufferAllocateInfo alloc_info{};
+    alloc_info.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
+    alloc_info.commandPool = command_pool_;
+    alloc_info.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
+    alloc_info.commandBufferCount = static_cast<uint32_t>(command_buffers_.size());
+
+    if (vkAllocateCommandBuffers(device_, &alloc_info, command_buffers_.data()) != VK_SUCCESS) {
+        throw std::runtime_error("Failed to allocate command buffers!");
+    }
+}
+
 /* end VulkanApp.cpp */
diff --git a/xo-imgui/example/ex4a/VulkanApp.hpp b/xo-imgui/example/ex4a/VulkanApp.hpp
index e3310f54..04f13f07 100644
--- a/xo-imgui/example/ex4a/VulkanApp.hpp
+++ b/xo-imgui/example/ex4a/VulkanApp.hpp
@@ -72,19 +72,10 @@ private:
      */
     void create_command_pool();
 
-    void create_command_buffers() {
-        commandBuffers.resize(MAX_FRAMES_IN_FLIGHT);
-
-        VkCommandBufferAllocateInfo allocInfo{};
-        allocInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
-        allocInfo.commandPool = command_pool_;
-        allocInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
-        allocInfo.commandBufferCount = static_cast<uint32_t>(commandBuffers.size());
-
-        if (vkAllocateCommandBuffers(device_, &allocInfo, commandBuffers.data()) != VK_SUCCESS) {
-            throw std::runtime_error("Failed to allocate command buffers!");
-        }
-    }
+    /*
+     * populate @ref command_buffers_
+     */
+    void create_command_buffers();
 
     void create_sync_objects() {
         imageAvailableSemaphores.resize(MAX_FRAMES_IN_FLIGHT);
@@ -245,8 +236,8 @@ private:
 
         vkResetFences(device_, 1, &inFlightFences[currentFrame]);
 
-        vkResetCommandBuffer(commandBuffers[currentFrame], 0);
-        recordCommandBuffer(commandBuffers[currentFrame], imageIndex);
+        vkResetCommandBuffer(command_buffers_[currentFrame], 0);
+        recordCommandBuffer(command_buffers_[currentFrame], imageIndex);
 
         VkSubmitInfo submitInfo{};
         submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
@@ -258,7 +249,7 @@ private:
         submitInfo.pWaitDstStageMask = waitStages;
 
         submitInfo.commandBufferCount = 1;
-        submitInfo.pCommandBuffers = &commandBuffers[currentFrame];
+        submitInfo.pCommandBuffers = &command_buffers_[currentFrame];
 
         VkSemaphore signalSemaphores[] = {renderFinishedSemaphores[currentFrame]};
         submitInfo.signalSemaphoreCount = 1;
@@ -453,7 +444,8 @@ private:
 
     VkCommandPool command_pool_;
 
-    std::vector<VkCommandBuffer> commandBuffers;
+    std::vector<VkCommandBuffer> command_buffers_;
+
     std::vector<VkSemaphore> imageAvailableSemaphores;
     std::vector<VkSemaphore> renderFinishedSemaphores;
     std::vector<VkFence> inFlightFences;