diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
new file mode 100644
index 0000000..74f3935
--- /dev/null
+++ b/.github/workflows/cmake.yml
@@ -0,0 +1,37 @@
+name: CMake
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+env:
+  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
+  BUILD_TYPE: Release
+
+jobs:
+  build:
+    # The CMake configure and build commands are platform agnostic and should work equally
+    # well on Windows or Mac.  You can convert this to a matrix build if you need
+    # cross-platform coverage.
+    # See: https://docs.github.com/en/free-pro-team@latest/actions/learn-github-actions/managing-complex-workflows#using-a-build-matrix
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    
+    - name: Install system dependencies
+      if: runner.os == 'Linux'
+      run: |
+        sudo apt-get update
+        sudo apt-get -y install libgtk-3-dev gettext
+
+    - name: Configure CMake
+      # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
+      # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+
+    - name: Build
+      # Build your program with the given configuration
+      run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}}
diff --git a/README.MD b/README.MD
index 008d39e..3ff07ba 100644
--- a/README.MD
+++ b/README.MD
@@ -1,5 +1,7 @@
 # GDS-Render Readme
 
+[![CMake](https://github.com/0mhu/gds-render/actions/workflows/cmake.yml/badge.svg?branch=master)](https://github.com/0mhu/gds-render/actions/workflows/cmake.yml)
+
 This software is a rendering programm for GDS2 layout files.
 The GDS2 format is mainly used in integrated circuit development.
 This program allows the conversion of a GDS file to a vector graphics file.
diff --git a/doxygen/compilation.dox b/doxygen/compilation.dox
index ca0ae2f..93b7e10 100644
--- a/doxygen/compilation.dox
+++ b/doxygen/compilation.dox
@@ -30,7 +30,7 @@ Development is done with the following library versions:
 
 | Cairographics | GLib2      | GTK3      |
 | ------------- | ---------- | --------- |
-| 1.17.3        | 2.60.6-1   | 3.24.10-1 |
+| 1.17.2        | 2.64.2     | 3.24.18   |
 
 @section comp-instr Compilation Instructions
 @subsection linux-build General Linux Build Instruction
@@ -47,7 +47,7 @@ Once cmake has finished, type
  make
 @endcode
 to build the program and 
-
+ 
 @code
  make documentation
 @endcode
@@ -59,7 +59,7 @@ The subfolder 'AUR' contains a PKGBUILD file to build an Archlinux/Pacman packag
 
 @subsection comp-warnings Compiler Warnings
 
-The compiler will throw the following warnings. Compiled with GCC 8.2.1.
+The compiler will throw the following warnings. Compiled with GCC 9.3.0.
 
 | Warning | Assessment |
 | ------- | ---------- |
diff --git a/gds-render-gui.c b/gds-render-gui.c
index a55b7e0..7802013 100644
--- a/gds-render-gui.c
+++ b/gds-render-gui.c
@@ -187,7 +187,8 @@ static gboolean cell_store_filter_visible_func(GtkTreeModel *model, GtkTreeIter
 
 	gtk_tree_model_get(model, iter, CELL_SEL_CELL, &cell, CELL_SEL_LIBRARY, &lib, -1);
 
-	if (lib) {
+    /* Show always, if this is a pure lib entry */
+    if (lib && !cell) {
 		result = TRUE;
 		goto exit_filter;
 	}
diff --git a/geometric/vector-operations.c b/geometric/vector-operations.c
index f3b0eb1..16580d8 100644
--- a/geometric/vector-operations.c
+++ b/geometric/vector-operations.c
@@ -65,7 +65,7 @@ void vector_2d_rotate(struct vector_2d *vec, double angle)
 	sin_val = sin(angle);
 	cos_val = cos(angle);
 
-	vector_2d_copy(&temp, vec);
+	(void)vector_2d_copy(&temp, vec);
 
 	/* Apply rotation matrix */
 	vec->x = (cos_val * temp.x) - (sin_val * temp.y);
diff --git a/layer/color-palette.c b/layer/color-palette.c
index ae51dae..2372e9c 100644
--- a/layer/color-palette.c
+++ b/layer/color-palette.c
@@ -238,6 +238,7 @@ static void color_palette_dispose(GObject *gobj)
 	if (palette->color_array) {
 		palette->color_array_length = 0;
 		free(palette->color_array);
+		palette->color_array = NULL;
 	}
 
 	/* Chain up to parent class */