diff --git a/README.md b/README.md
index d702e3e..0b2c352 100644
--- a/README.md
+++ b/README.md
@@ -57,3 +57,9 @@ Troubleshooting:
 1. `makers bundle`
 2. Runnable executable is in `target/release`
 3. Installable bundles specific for the platform are in `target/release/bundle`
+
+---
+
+### Test files
+
+See the folder `test_files`.
diff --git a/frontend/typescript/pixi_canvas/pixi_canvas.ts b/frontend/typescript/pixi_canvas/pixi_canvas.ts
index 0bbf883..cb69e41 100644
--- a/frontend/typescript/pixi_canvas/pixi_canvas.ts
+++ b/frontend/typescript/pixi_canvas/pixi_canvas.ts
@@ -174,7 +174,7 @@ class VarSignalRow {
     }
 
     draw() {
-        // Screen can be null when we are, for instance, switching between miller column and tree layout
+        // Screen can be null when we are, for instance, switching between miller columns and tree layout
         // and then the canvas has to be recreated
         if (this.app.screen === null) {
             return;
@@ -182,6 +182,7 @@ class VarSignalRow {
 
         this.row_container_background.width = this.app.screen.width;
 
+        // @TODO optimize by reusing a pool of blocks instead or removing all children on every redraw?
         this.signal_blocks_container.removeChildren();
         this.timeline.blocks.forEach(timeline_block => {
             // signal_block