diff --git a/src/lang/english.txt b/src/lang/english.txt
index 887d99adb0..92ff143261 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -4212,6 +4212,8 @@ STR_NEWGRF_INSPECT_REFRESH                                      :{BLACK}R
 STR_NEWGRF_INSPECT_REFRESH_TOOLTIP                              :{BLACK}Toggle whether to refresh the contents every frame
 STR_NEWGRF_INSPECT_LOG_CONSOLE                                  :{BLACK}L
 STR_NEWGRF_INSPECT_LOG_CONSOLE_TOOLTIP                          :{BLACK}Log text content of this window to the console
+STR_NEWGRF_INSPECT_DUPLICATE                                    :{BLACK}D
+STR_NEWGRF_INSPECT_DUPLICATE_TOOLTIP                            :{BLACK}Duplicate this window
 STR_NEWGRF_INSPECT_SPRITE_DUMP                                  :{BLACK}S
 STR_NEWGRF_INSPECT_SPRITE_DUMP_TOOLTIP                          :{BLACK}Display current sprite chain
 STR_NEWGRF_INSPECT_SPRITE_DUMP_PANEL_TOOLTIP                    :{BLACK}Click to highlight sprite group{}Shift+Click to collapse sprite group{}Ctrl+Click to highlight temporary storage register
diff --git a/src/newgrf_debug_gui.cpp b/src/newgrf_debug_gui.cpp
index 38da3b2bdf..5d95b589ff 100644
--- a/src/newgrf_debug_gui.cpp
+++ b/src/newgrf_debug_gui.cpp
@@ -831,6 +831,12 @@ struct NewGRFInspectWindow : Window {
 				break;
 			}
 
+			case WID_NGRFI_DUPLICATE: {
+				NewGRFInspectWindow *w = new NewGRFInspectWindow(this->window_desc, this->window_number);
+				w->SetCallerGRFID(this->caller_grfid);
+				break;
+			}
+
 			case WID_NGRFI_SPRITE_DUMP: {
 				this->sprite_dump = !this->sprite_dump;
 				this->SetWidgetLoweredState(WID_NGRFI_SPRITE_DUMP, this->sprite_dump);
@@ -887,6 +893,7 @@ static const NWidgetPart _nested_newgrf_inspect_chain_widgets[] = {
 		NWidget(NWID_SELECTION, INVALID_COLOUR, WID_NGRFI_SPRITE_DUMP_SEL),
 			NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_NGRFI_SPRITE_DUMP), SetDataTip(STR_NEWGRF_INSPECT_SPRITE_DUMP, STR_NEWGRF_INSPECT_SPRITE_DUMP_TOOLTIP),
 		EndContainer(),
+		NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_NGRFI_DUPLICATE), SetDataTip(STR_NEWGRF_INSPECT_DUPLICATE, STR_NEWGRF_INSPECT_DUPLICATE_TOOLTIP),
 		NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_NGRFI_LOG_CONSOLE), SetDataTip(STR_NEWGRF_INSPECT_LOG_CONSOLE, STR_NEWGRF_INSPECT_LOG_CONSOLE_TOOLTIP),
 		NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_NGRFI_REFRESH), SetDataTip(STR_NEWGRF_INSPECT_REFRESH, STR_NEWGRF_INSPECT_REFRESH_TOOLTIP),
 		NWidget(WWT_SHADEBOX, COLOUR_GREY),
@@ -917,6 +924,7 @@ static const NWidgetPart _nested_newgrf_inspect_widgets[] = {
 		NWidget(NWID_SELECTION, INVALID_COLOUR, WID_NGRFI_SPRITE_DUMP_SEL),
 			NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_NGRFI_SPRITE_DUMP), SetDataTip(STR_NEWGRF_INSPECT_SPRITE_DUMP, STR_NEWGRF_INSPECT_SPRITE_DUMP_TOOLTIP),
 		EndContainer(),
+		NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_NGRFI_DUPLICATE), SetDataTip(STR_NEWGRF_INSPECT_DUPLICATE, STR_NEWGRF_INSPECT_DUPLICATE_TOOLTIP),
 		NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_NGRFI_LOG_CONSOLE), SetDataTip(STR_NEWGRF_INSPECT_LOG_CONSOLE, STR_NEWGRF_INSPECT_LOG_CONSOLE_TOOLTIP),
 		NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_NGRFI_REFRESH), SetDataTip(STR_NEWGRF_INSPECT_REFRESH, STR_NEWGRF_INSPECT_REFRESH_TOOLTIP),
 		NWidget(WWT_SHADEBOX, COLOUR_GREY),
@@ -997,7 +1005,7 @@ void DeleteNewGRFInspectWindow(GrfSpecFeature feature, uint index)
 	if (index >= (1 << 27)) return;
 
 	WindowNumber wno = GetInspectWindowNumber(feature, index);
-	DeleteWindowById(WC_NEWGRF_INSPECT, wno);
+	DeleteAllWindowsById(WC_NEWGRF_INSPECT, wno);
 
 	/* Reinitialise the land information window to remove the "debug" sprite if needed.
 	 * Note: Since we might be called from a command here, it is important to not execute
diff --git a/src/widgets/newgrf_debug_widget.h b/src/widgets/newgrf_debug_widget.h
index 49b162269c..fcf45dfc0d 100644
--- a/src/widgets/newgrf_debug_widget.h
+++ b/src/widgets/newgrf_debug_widget.h
@@ -21,6 +21,7 @@ enum NewGRFInspectWidgets {
 	WID_NGRFI_SCROLLBAR, ///< Scrollbar.
 	WID_NGRFI_REFRESH,   ///< Refresh toggle.
 	WID_NGRFI_LOG_CONSOLE, ///< Log to console
+	WID_NGRFI_DUPLICATE, ///< Duplicate window
 	WID_NGRFI_SPRITE_DUMP, ///< Dump current sprite group
 	WID_NGRFI_SPRITE_DUMP_SEL, ///< Selection widget for WID_NGRFI_SPRITE_DUMP
 };
diff --git a/src/window.cpp b/src/window.cpp
index dd1ba33ee0..cef50f2531 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -1193,6 +1193,22 @@ void DeleteWindowById(WindowClass cls, WindowNumber number, bool force)
 	}
 }
 
+/**
+ * Delete all windows of its class and window number (if open).
+ * @param cls Window class
+ * @param number Number of the window within the window class
+ * @param force force deletion; if false don't delete when stickied
+ */
+void DeleteAllWindowsById(WindowClass cls, WindowNumber number, bool force)
+{
+	/* Note: the container remains stable, even when deleting windows. */
+	for (Window *w : Window::IterateUnordered()) {
+		if (w->window_class == cls && w->window_number == number && (force || (w->flags & WF_STICKY) == 0)) {
+			delete w;
+		}
+	}
+}
+
 /**
  * Delete all windows of a given class
  * @param cls Window class of windows to delete
diff --git a/src/window_func.h b/src/window_func.h
index d63b4f6af2..c16d041073 100644
--- a/src/window_func.h
+++ b/src/window_func.h
@@ -54,6 +54,7 @@ void SetWindowDirty(WindowClass cls, WindowNumber number);
 void SetWindowClassesDirty(WindowClass cls);
 
 void DeleteWindowById(WindowClass cls, WindowNumber number, bool force = true);
+void DeleteAllWindowsById(WindowClass cls, WindowNumber number, bool force = true);
 void DeleteWindowByClass(WindowClass cls);
 
 bool FocusWindowById(WindowClass cls, WindowNumber number);