diff --git a/canvasblocker.xpi b/canvasblocker.xpi
index a8db77f..44c3ce4 100644
Binary files a/canvasblocker.xpi and b/canvasblocker.xpi differ
diff --git a/data/inject.js b/data/inject.js
index df8b82d..8eb466e 100644
--- a/data/inject.js
+++ b/data/inject.js
@@ -2,6 +2,9 @@
 (function(){
 	"use strict";
 	
+	var settings = {
+		showCallingFile: false
+	};
 	var blockMode = {
 		getContext: {
 			status: "block",
@@ -147,12 +150,32 @@
 							status = askStatus.answer;
 						}
 						else {
+							//console.log("asking");
 							var appearance = canvasAppearance(this);
-							// console.log("asking");
-							status = window.confirm(_(changedFunction.mode.askText[appearance.text]))? "allow": "block";
+							var msg = _(changedFunction.mode.askText[appearance.text]);
+							if (settings.showCallingFile){
+								var callers = new Error().stack.trim().split("\n");
+								//console.log(callers);
+								var findme = callers.shift(); // Remove us from the stack
+								findme = findme.replace(/(:[0-9]+){1,2}$/, ""); // rm line & column
+								// Eliminate squashed stack. stack may contain 2+ stacks, but why...
+								callers = callers.filter(function(caller){
+									return caller.search(findme) === -1;
+								});
+								msg += "\n\n" + _("sourceOutput") + ": ";
+								if (settings.showCompleteCallingStack){
+									msg += callers.reduce(function(stack, c){
+										return stack + "\n\t" + _("stackEntryOutput", parseStackEntry(c));
+									}, "");
+								}
+								else{
+									msg += _("stackEntryOutput", parseStackEntry(callers[0]));
+								}
+							}
+							status = window.confirm(msg) ? "allow": "block";
 							askStatus.alreadyAsked = true;
 							askStatus.answer = status;
-							
+							//console.log("asking (done)");
 							appearance.reset();
 						}
 					}
@@ -174,9 +197,26 @@
 		);
 	});
 	
+	// Stack parsing
+	function parseStackEntry(entry){
+		var m = /@(.*):(\d*):(\d*)$/.exec(entry) || ["", entry, "--", "--"];
+		return {
+			url: m[1],
+			line: m[2],
+			column: m[3],
+			raw: entry
+		};
+	}
+	
 	// Translation
-	var _ = function(name){
-		return _[name] || name;
+	var _ = function(name, replace){
+		var str = _[name] || name;
+		if (replace){
+			Object.keys(replace).forEach(function(name){
+				str = str.replace(new RegExp("{" + name + "}", "g"), replace[name]);
+			});
+		}
+		return str;
 	};
 	self.port.on("setTranslation", function(name, translation){
 		_[name] = translation;
@@ -232,4 +272,9 @@
 		blockMode.getContext.status = "allow";
 		blockMode.readAPI.status = "allow";
 	});
+	
+	// settings passthrough
+	self.port.on("set", function(name, value){
+		settings[name] = value;
+	});
 }());
diff --git a/lib/main.js b/lib/main.js
index 81294b4..36a47ec 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -73,6 +73,16 @@
 		updateBlackList();
 	});
 	
+	// preferences for injected file
+	var preferencesForInjected = ["showCallingFile", "showCompleteCallingStack"];
+	preferencesForInjected.forEach(function(name){
+		preferences.on(name, function(){
+			workers.forEach(function(worker){
+				worker.port.emit("set", name, prefs[name]);
+			});
+		});
+	});
+	
 	function checkURL(url){
 		var url = new URL(url);
 		var mode = "block";
@@ -159,6 +169,12 @@
 						worker.port.emit("setTranslation", text, _(text));
 				});
 			});
+			worker.port.emit("setTranslation", "sourceOutput", _("sourceOutput"));
+			worker.port.emit("setTranslation", "stackEntryOutput", _("stackEntryOutput"));
+			
+			preferencesForInjected.forEach(function(name){
+				worker.port.emit("set", name, prefs[name]);
+			});
 			
 			checkWorker(worker);
 		},
diff --git a/locale/de-DE.properties b/locale/de-DE.properties
index 083c1e4..85b2e31 100644
--- a/locale/de-DE.properties
+++ b/locale/de-DE.properties
@@ -19,6 +19,12 @@ blockMode_options.allow everything= alles erlauben
 askOnlyOnce_title= Nur einmal nachfragen
 askOnlyOnce_description= Wenn eine Seite öfters versucht, die <canvas>-API abzurufen, erscheint jedes mal eine Nachfrage. Mit diesem Schalter wird pro Seitenbesuch nur einmal nachgefragt. Bei manchen Seiten kann es trotzdem zu mehrmaligem Nachfragen kommen. 
 
+showCallingFile_title= Aufrufende Datei anzeigen
+showCallingFile_description=
+
+showCompleteCallingStack_title= Kompletten Aufrufestack anzeigen
+showCompleteCallingStack_description=
+
 allowPDFCanvas_title= <canvas> in PDFs erlauben
 allowPDFCanvas_description= Die native pdf.js verwendet <canvas> um den Inhalt von PDFs anzuzeigen. Wenn dies nicht markiert ist, werden viele Nachfragedialoge erscheinen oder die PDF Ansicht nicht funktionieren.
 
@@ -27,4 +33,7 @@ askForVisiblePermission= Wollen Sie das rot umrandete <canvas> erlauben?
 askForInvisiblePermission= Wollen Sie unsichtbare <canvas> erlauben?
 askForReadoutPermission= Wollen Sie das Auslesen von <canvas> erlauben?
 askForVisibleReadoutPermission= Wollen Sie das Auslesen des rot umrandeten <canvas> erlauben?
-askForInvisibleReadoutPermission= Wollen Sie das Auslesen von unsichtbaren <canvas> erlauben?
\ No newline at end of file
+askForInvisibleReadoutPermission= Wollen Sie das Auslesen von unsichtbaren <canvas> erlauben?
+
+sourceOutput= Aufrufende Datei
+stackEntryOutput= {url} Zeile {line} Spalte {column}
\ No newline at end of file
diff --git a/locale/en-US.properties b/locale/en-US.properties
index 0793112..2d1bdb9 100644
--- a/locale/en-US.properties
+++ b/locale/en-US.properties
@@ -19,6 +19,12 @@ blockMode_options.allow everything= allow everything
 askOnlyOnce_title= Ask only once
 askOnlyOnce_description= If a page tries to access the <canvas>-API several times a confirm message will appear every time. This switch tries to make only one confirmation. Never the less on some pages there will be more.
 
+showCallingFile_title= Show calling file
+showCallingFile_description=
+
+showCompleteCallingStack_title= Display complete calling stack
+showCompleteCallingStack_description=
+
 allowPDFCanvas_title= Allow canvas in PDFs
 allowPDFCanvas_description= The native pdf.js uses <canvas> to display the PDF content. If this is unchecked there will lots of annoying ask dialogs or the PDF display will not work.
 
@@ -27,4 +33,7 @@ askForVisiblePermission= Do you want to allow the red bordered <canvas>?
 askForInvisiblePermission= Do you want to allow invisible <canvas>?
 askForReadoutPermission= Do you want to allow <canvas> readout?
 askForVisibleReadoutPermission= Do you want to allow the readout of the red bordered <canvas>?
-askForInvisibleReadoutPermission= Do you want to allow invisible <canvas> readout?
\ No newline at end of file
+askForInvisibleReadoutPermission= Do you want to allow invisible <canvas> readout?
+
+sourceOutput= Calling file
+stackEntryOutput= {url} line {line} column {column}
\ No newline at end of file
diff --git a/package.json b/package.json
index db6f712..5200844 100644
--- a/package.json
+++ b/package.json
@@ -62,6 +62,18 @@
 			"type": "bool",
 			"value": true
 		},
+		{
+			"name": "showCallingFile",
+			"title": "Display calling file",
+			"type": "bool",
+			"value": false
+		},
+		{
+			"name": "showCompleteCallingStack",
+			"title": "Display complete calling stack",
+			"type": "bool",
+			"value": false
+		},
 		{
 			"name": "allowPDFCanvas",
 			"title": "Allow canvas in PDFs",