diff --git a/engine/cairoShim.h b/engine/cairoShim.h
index 47e8a3bfb..d185fa836 100644
--- a/engine/cairoShim.h
+++ b/engine/cairoShim.h
@@ -17,41 +17,42 @@ namespace minsky
   class ICairoShim
   {
   public:
-    volatile void moveTo(double x, double y)=0;
-    volatile void lineTo(double x, double y)=0;
-    volatile void relMoveTo(double x, double y)=0;
-    volatile void relLineTo(double x, double y)=0;
-    volatile void arc(double x, double y, double radius, double start, double end)=0;
+    virtual ~ICairoShim() = default;
+    virtual void moveTo(double x, double y)=0;
+    virtual void lineTo(double x, double y)=0;
+    virtual void relMoveTo(double x, double y)=0;
+    virtual void relLineTo(double x, double y)=0;
+    virtual void arc(double x, double y, double radius, double start, double end)=0;
 
-    volatile void setLineWidth(double)=0;
+    virtual void setLineWidth(double)=0;
 
     // paths
-    volatile void newPath()=0;
-    volatile void closePath()=0;
-    volatile void fill()=0;
-    volatile void clip()=0;
-    volatile void stroke()=0;
-    volatile void strokePreserve()=0;
+    virtual void newPath()=0;
+    virtual void closePath()=0;
+    virtual void fill()=0;
+    virtual void clip()=0;
+    virtual void stroke()=0;
+    virtual void strokePreserve()=0;
 
     // sources
-    volatile void setSourceRGB(double r, double g, double b)=0;
-    volatile void setSourceRGBA(double r, double g, double b, double a)=0;
+    virtual void setSourceRGB(double r, double g, double b)=0;
+    virtual void setSourceRGBA(double r, double g, double b, double a)=0;
     
     // text. Argument is in UTF8 encoding
-    volatile void showText(const std::string&)=0;
-    volatile void setTextExtents(const std::string&)=0;
-    volatile double textWidth() const=0;
-    volatile double textHeight() const=0;
+    virtual void showText(const std::string&)=0;
+    virtual void setTextExtents(const std::string&)=0;
+    virtual double textWidth() const=0;
+    virtual double textHeight() const=0;
 
     // matrix transformation
-    volatile void identityMatrix()=0;
-    volatile void translate(double x, double y)=0;
-    volatile void scale(double sx, double sy)=0;
-    volatile void rotate(double angle)=0; ///< angle in radians
+    virtual void identityMatrix()=0;
+    virtual void translate(double x, double y)=0;
+    virtual void scale(double sx, double sy)=0;
+    virtual void rotate(double angle)=0; ///< angle in radians
 
     // context manipulation
-    volatile void save()=0;
-    volatile void restore()=0;
+    virtual void save()=0;
+    virtual void restore()=0;
     
   };
 
diff --git a/package-lock.json b/package-lock.json
index 283967596..a3ea4db8a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -92,6 +92,7 @@
       "integrity": "sha512-ENHwaH+JIRTDIEEbDK6QSQntAYGtbvdDXnMXnZaZ6k13Du1dPMmprkEHIL7ok2Wl2aZevetwTAb5S+7yIF+enA==",
       "dev": true,
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "undici-types": "~7.8.0"
       }
@@ -227,6 +228,7 @@
       "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.8.3.tgz",
       "integrity": "sha512-p1diW6TqL9L07nNxvRMM7hMMw4c5XOo/1ibL4aAIGmSAt9slTE1Xgw5KWuof2uTOvCg9BY7ZRi+GaF+7sfgPeQ==",
       "license": "Apache-2.0",
+      "peer": true,
       "bin": {
         "tsc": "bin/tsc",
         "tsserver": "bin/tsserver"