diff --git a/imgui/src/docking_utils.rs b/imgui/src/docking_utils.rs
index c3047cc..e5d0fd3 100644
--- a/imgui/src/docking_utils.rs
+++ b/imgui/src/docking_utils.rs
@@ -2,7 +2,7 @@ use std::{
     cell::UnsafeCell,
     ffi::{c_void, CStr},
     os::raw::{c_char, c_int},
-    sync::{Mutex, MutexGuard},
+    sync::Mutex,
 };
 
 use crate::{PlatformIo, Viewport};
@@ -175,92 +175,11 @@ pub(crate) extern "C" fn platform_create_vk_surface(
         })
 }
 
-/// The default [`PlatformViewportBackend`], does nothing.
-pub(crate) struct DummyPlatformViewportBackend {}
-impl PlatformViewportBackend for DummyPlatformViewportBackend {
-    fn create_window(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn destroy_window(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn show_window(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn set_window_pos(&mut self, _viewport: &mut Viewport, _pos: [f32; 2]) {
-        unimplemented!()
-    }
-
-    fn get_window_pos(&mut self, _viewport: &mut Viewport) -> [f32; 2] {
-        unimplemented!()
-    }
-
-    fn set_window_size(&mut self, _viewport: &mut Viewport, _size: [f32; 2]) {
-        unimplemented!()
-    }
-
-    fn get_window_size(&mut self, _viewport: &mut Viewport) -> [f32; 2] {
-        unimplemented!()
-    }
-
-    fn set_window_focus(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn get_window_focus(&mut self, _viewport: &mut Viewport) -> bool {
-        unimplemented!()
-    }
-
-    fn get_window_minimized(&mut self, _viewport: &mut Viewport) -> bool {
-        unimplemented!()
-    }
-
-    fn set_window_title(&mut self, _viewport: &mut Viewport, _title: &str) {
-        unimplemented!()
-    }
-
-    fn set_window_alpha(&mut self, _viewport: &mut Viewport, _alpha: f32) {
-        unimplemented!()
-    }
-
-    fn update_window(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn render_window(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn swap_buffers(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn create_vk_surface(
-        &mut self,
-        _viewport: &mut Viewport,
-        _instance: u64,
-        _out_surface: &mut u64,
-    ) -> i32 {
-        unimplemented!()
-    }
-}
-
 /// Just holds a [`PlatformViewportBackend`].
 pub(crate) struct PlatformViewportContext {
     pub(crate) backend: Box<dyn PlatformViewportBackend>,
 }
 
-impl PlatformViewportContext {
-    pub(crate) fn dummy() -> Self {
-        Self {
-            backend: Box::new(DummyPlatformViewportBackend {}),
-        }
-    }
-}
-
 unsafe impl Send for PlatformViewportContext {}
 
 /// Trait that holds optional functions for a rendering backend to support multiple viewports.
@@ -299,43 +218,11 @@ pub(crate) extern "C" fn renderer_swap_buffers(viewport: *mut Viewport, _arg: *m
     ctx.backend.swap_buffers(unsafe { &mut *viewport });
 }
 
-/// The default [`RendererViewportBackend`], does nothing.
-pub(crate) struct DummyRendererViewportBackend {}
-impl RendererViewportBackend for DummyRendererViewportBackend {
-    fn create_window(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn destroy_window(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn set_window_size(&mut self, _viewport: &mut Viewport, _size: [f32; 2]) {
-        unimplemented!()
-    }
-
-    fn render_window(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-
-    fn swap_buffers(&mut self, _viewport: &mut Viewport) {
-        unimplemented!()
-    }
-}
-
 /// Just holds a [`RendererViewportBackend`].
 pub(crate) struct RendererViewportContext {
     pub(crate) backend: Box<dyn RendererViewportBackend>,
 }
 
-impl RendererViewportContext {
-    pub(crate) fn dummy() -> Self {
-        Self {
-            backend: Box::new(DummyRendererViewportBackend {}),
-        }
-    }
-}
-
 unsafe impl Send for RendererViewportContext {}
 
 /// Describes a monitor that can be used by ImGui.