diff --git a/src/gui/core/event/distributor.cpp b/src/gui/core/event/distributor.cpp
index 6796d05977db..0fb2784adc1f 100644
--- a/src/gui/core/event/distributor.cpp
+++ b/src/gui/core/event/distributor.cpp
@@ -371,7 +371,7 @@ mouse_button<T>::mouse_button(const std::string& name_, widget& owner,
 	: mouse_motion(owner, queue_position)
 	, last_click_stamp_(0)
 	, last_clicked_widget_(nullptr)
-	, focus_(0)
+	, focus_(nullptr)
 	, name_(name_)
 	, is_down_(false)
 	, signal_handler_sdl_button_down_entered_(false)
@@ -549,8 +549,8 @@ distributor::distributor(widget& owner,
 	, hover_id_(0)
 	, hover_box_()
 	, had_hover_(false)
-	, tooltip_(0)
-	, help_popup_(0)
+	, tooltip_(nullptr)
+	, help_popup_(nullptr)
 #endif
 	, keyboard_focus_(nullptr)
 	, keyboard_focus_chain_()
diff --git a/src/gui/core/window_builder.cpp b/src/gui/core/window_builder.cpp
index f4513e477576..8ed9bd25dc8f 100644
--- a/src/gui/core/window_builder.cpp
+++ b/src/gui/core/window_builder.cpp
@@ -372,7 +372,7 @@ builder_window::window_resolution::window_resolution(const config& cfg)
 	, linked_groups()
 	, tooltip(cfg.child_or_empty("tooltip"), "tooltip")
 	, helptip(cfg.child_or_empty("helptip"), "helptip")
-	, grid(0)
+	, grid(nullptr)
 {
 	if(!cfg["functions"].empty()) {
 		wfl::formula(cfg["functions"], &functions).evaluate();
diff --git a/src/gui/widgets/window.cpp b/src/gui/widgets/window.cpp
index 305b036ba877..d6226e576f80 100644
--- a/src/gui/widgets/window.cpp
+++ b/src/gui/widgets/window.cpp
@@ -296,7 +296,7 @@ window::window(CVideo& video, const builder_window::window_resolution* definitio
 	, status_(NEW)
 	, show_mode_(none)
 	, retval_(NONE)
-	, owner_(0)
+	, owner_(nullptr)
 	, need_layout_(true)
 	, variables_()
 	, invalidate_layout_blocked_(false)