diff --git a/README.md b/README.md
index dee023f..4fedbb2 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ A simple script is provided to check for errors during development at [`./reacti
 
 In order to format the code in a uniform way run `cargo +nightly fmt`.
 
-To run the program use `cargo r`; to run the release build use `cargo r --relase`.
+To run the program use `cargo r`; to run the release build use `cargo r --release`.
 
 ## Native Application
 
diff --git a/reaction_systems_gui/src/app_logic.rs b/reaction_systems_gui/src/app_logic.rs
index 31727a6..2499aa9 100644
--- a/reaction_systems_gui/src/app_logic.rs
+++ b/reaction_systems_gui/src/app_logic.rs
@@ -109,7 +109,9 @@ fn generate_to_evaluate(
         let mut input_hashes = vec![];
 
         match graph[n_id].user_data.template {
-            | NodeInstruction::SaveString | NodeInstruction::SaveSvg => {
+            | NodeInstruction::SaveString |
+            NodeInstruction::SaveSvg |
+            NodeInstruction::SaveRasterization => {
                 res.push(n_id);
                 invalid_ids.insert(n_id);
                 outputs_cache.invalidate_outputs(graph, n_id);
diff --git a/reaction_systems_gui/src/svg.rs b/reaction_systems_gui/src/svg.rs
index 05dead1..728a147 100644
--- a/reaction_systems_gui/src/svg.rs
+++ b/reaction_systems_gui/src/svg.rs
@@ -26,6 +26,9 @@ pub(crate) struct Svg {
 
 impl Svg {
     pub(crate) fn parse_dot_string(dot_str: &str) -> Result<Svg, String> {
+        if dot_str.is_empty() {
+            return Err("Dot string is empty".into());
+        }
         let mut fontdb = fontdb::Database::new();
         fontdb.load_system_fonts();
 
@@ -43,6 +46,9 @@ impl Svg {
         gb.visit_graph(&g);
         let mut graph = gb.get();
         let mut svg = SVGWriter::new();
+        if graph.num_nodes() == 0 {
+           return Err("No nodes in dot graph".into());
+        }
         graph.do_it(false, false, false, &mut svg);
         // convert svg to string
         let content = svg.finalize();