diff --git a/osx/BoE.xcodeproj/project.pbxproj b/osx/BoE.xcodeproj/project.pbxproj
index 7ae5689d..f187a66a 100644
--- a/osx/BoE.xcodeproj/project.pbxproj
+++ b/osx/BoE.xcodeproj/project.pbxproj
@@ -2758,6 +2758,7 @@
 					"-ferror-limit=0",
 					"-Werror=format",
 					"-ftemplate-backtrace-limit=0",
+					"-Werror=return-type",
 				);
 				OTHER_LDFLAGS = (
 					"-lboost_filesystem",
@@ -2810,6 +2811,7 @@
 					"-ferror-limit=0",
 					"-Werror=format",
 					"-ftemplate-backtrace-limit=0",
+					"-Werror=return-type",
 				);
 				OTHER_LDFLAGS = (
 					"-lboost_filesystem",
diff --git a/osx/boe.dlgutil.cpp b/osx/boe.dlgutil.cpp
index 217d3189..8b799a83 100644
--- a/osx/boe.dlgutil.cpp
+++ b/osx/boe.dlgutil.cpp
@@ -1183,6 +1183,7 @@ bool prefs_event_filter (cDialog& me, std::string id, eKeyMod mods)
 		give_delays = PSD[SDF_NO_FRILLS];
 		save_prefs(reset_help);
 		}
+	return true;
 }
 
 void pick_preferences()
diff --git a/osx/boe.infodlg.cpp b/osx/boe.infodlg.cpp
index a5429a25..32513951 100644
--- a/osx/boe.infodlg.cpp
+++ b/osx/boe.infodlg.cpp
@@ -121,6 +121,7 @@ bool display_spells_event_filter(cDialog& me, std::string item_hit, eKeyMod mods
 						else priest_spell_pos = store;
 					put_spell_info(me, display_mode);
 				}
+	return true;
 }
 void display_spells(short mode,short force_spell,cDialog* parent)
 //short mode; // 0 - mage  1 - priest
@@ -180,6 +181,7 @@ bool display_skills_event_filter(cDialog& me, std::string item_hit, eKeyMod mods
 							}
 					put_skill_info(me);
 				}
+	return true;
 }
 
 void display_skills(short force_skill,cDialog* parent)
@@ -235,6 +237,7 @@ bool display_pc_event_filter(cDialog& me, std::string item_hit, eKeyMod mods)
 					which_pc_displayed = pc_num;
 					put_pc_spells(me);
 				}
+	return true;
 }
 
 void display_pc(short pc_num,short mode,cDialog* parent)
@@ -413,6 +416,7 @@ bool display_pc_item_event_filter(cDialog& me, std::string item_hit, eKeyMod mod
 					store_i = univ.party[pc_num].items[item];
 					put_item_info(me,pc_num,item);
 	}
+	return true;
 }
 
 void display_pc_item(short pc_num,short item,cItemRec si,short parent)
@@ -555,6 +559,7 @@ bool display_monst_event_filter(cDialog& me, std::string item_hit, eKeyMod mods)
 		// TODO: It may not be redudndant, but it looks pretty stupid; change it
 		put_monst_info(me);
 				}
+	return true;
 }
 
 void display_monst(short array_pos,cCreature *which_m,short mode)
@@ -632,6 +637,7 @@ bool display_alchemy_event_filter(cDialog& me, std::string item_hit, eKeyMod mod
 	}
 	get_text = get_str("alchemy", cur_entry);
 	me["str"].setText(get_text);
+	return true;
 }
 
 void display_alchemy(cDialog* parent)
@@ -875,6 +881,7 @@ bool give_pc_info_event_filter(cDialog& me, std::string item_hit, eKeyMod mods)
 				while (univ.party[store_pc_num].main_status != 1);
 			display_pc_info(me);
 	}
+	return true;
 }
 
 bool give_pc_extra_info(cDialog& me, std::string item_hit, eKeyMod mods) {
@@ -883,6 +890,7 @@ bool give_pc_extra_info(cDialog& me, std::string item_hit, eKeyMod mods) {
 	else if(item_hit == "seepriest") display_pc(pc,1,&me);
 	else if(item_hit == "trait") pick_race_abil(&univ.party[pc],1,&me);
 	else if(item_hit == "alch") display_alchemy();
+	return true;
 }
 
 void give_pc_info(short pc_num)
@@ -978,6 +986,7 @@ bool adventure_notes_event_filter(cDialog& me, std::string item_hit, eKeyMod mod
 				me["del" + n].hide();
 				}
 		}
+	return true;
 }
 
 void adventure_notes()
@@ -1087,6 +1096,7 @@ bool talk_notes_event_filter(cDialog& me, std::string item_hit, eKeyMod mods)
 					univ.party.talk_save[store_page_on].personality = -1;
 				}
 	put_talk(me);
+	return true;
 }
 
 void talk_notes()
@@ -1146,7 +1156,7 @@ bool journal_event_filter(cDialog& me, std::string item_hit, eKeyMod mods)
 			me["day" + n].setText("");
 		}
 	}
-
+	return true;
 }
 
 void journal()
diff --git a/osx/boe.items.cpp b/osx/boe.items.cpp
index c3d451ad..3b6c77a6 100644
--- a/osx/boe.items.cpp
+++ b/osx/boe.items.cpp
@@ -1014,7 +1014,7 @@ bool display_item_event_filter(cDialog& me, std::string id, eKeyMod mods)
 		total_items_gettable--;
 		put_item_graphics(me);
 	}
-		
+	return true;
 }
 
 // TODO: Move this to a more appropriate place
@@ -1112,6 +1112,7 @@ short custom_choice_dialog(std::array<std::string, 6>& strs,short pic_num,ePicTy
 		if(btn && item_hit == btn->label)
 			return i;
 	}
+	return -1;
 	}
 
 //short fancy_choice_dialog(short which_dlog,short parent)
diff --git a/osx/boe.party.cpp b/osx/boe.party.cpp
index e0cb41e7..e31a4083 100644
--- a/osx/boe.party.cpp
+++ b/osx/boe.party.cpp
@@ -1085,6 +1085,7 @@ bool spend_xp_navigate_filter(cDialog& me, std::string item_hit, eKeyMod mods)
 	if (talk_done == true) {
 		me.toast();
 	}
+	return true;
 }
 
 bool spend_xp_event_filter(cDialog& me, std::string item_hit, eKeyMod mods) {
@@ -1193,6 +1194,7 @@ bool spend_xp_event_filter(cDialog& me, std::string item_hit, eKeyMod mods) {
 						}
 				}
 			}
+	return true;
 }
 
 bool spend_xp(short pc_num, short mode, cDialog* parent)
@@ -2498,6 +2500,7 @@ bool pick_spell_caster(cDialog& me, std::string id, eKeyMod mods) {
 	put_pc_caster_buttons(me);
 	put_pc_target_buttons(me);
 					}
+	return true;
 }
 
 bool pick_spell_target(cDialog& me, std::string id, eKeyMod mods) {
@@ -2517,6 +2520,7 @@ bool pick_spell_target(cDialog& me, std::string id, eKeyMod mods) {
 		draw_spell_info(me);
 		put_pc_target_buttons(me);
 	}
+	return true;
 }
 
 void finish_pick_spell(cDialog& me, bool spell_toast);
@@ -2537,6 +2541,7 @@ bool pick_spell_event_filter(cDialog& me, std::string item_hit, eKeyMod mods) {
 		give_help(207,8,me);
 	}
 	if(dialog_done) finish_pick_spell(me, spell_toast);
+	return true;
 }
 
 bool pick_spell_select_led(cDialog& me, std::string id, eKeyMod mods) {
@@ -2578,6 +2583,7 @@ bool pick_spell_select_led(cDialog& me, std::string id, eKeyMod mods) {
 								}
 
 						}
+	return true;
 }
 
 void finish_pick_spell(cDialog& me, bool spell_toast) {
@@ -2910,6 +2916,7 @@ bool alch_choice_event_filter(cDialog& me, std::string item_hit, eKeyMod mods)
 			me.setResult<short>(item_hit[6] - '1');
 		}
 	me.toast();
+	return true;
 }
 
 short alch_choice(short pc_num)
@@ -2986,7 +2993,7 @@ bool pc_name_event_filter(cDialog& me, std::string item_hit, eKeyMod mods)
 			univ.party[store_train_pc].name = pcName;
 			me.toast();
 			}
-
+	return true;
 }
 
 bool pick_pc_name(short pc_num,cDialog* parent)
diff --git a/osx/dialogxml/button.cpp b/osx/dialogxml/button.cpp
index 19306425..55e912e0 100644
--- a/osx/dialogxml/button.cpp
+++ b/osx/dialogxml/button.cpp
@@ -104,6 +104,7 @@ void cButton::setColour(sf::Color clr) throw(xUnsupportedProp) {
 
 sf::Color cButton::getColour() throw(xUnsupportedProp) {
 	// TODO: Colour is not supported
+	return sf::Color();
 }
 
 void cButton::setBtnType(eBtnType newType) {
@@ -397,6 +398,7 @@ void cLedGroup::setColour(sf::Color clr) throw(xUnsupportedProp) {
 
 sf::Color cLedGroup::getColour() throw(xUnsupportedProp) {
 	// TODO: Colour is not supported
+	return sf::Color();
 }
 
 bool cLedGroup::isClickable(){
diff --git a/osx/dialogxml/dialog.cpp b/osx/dialogxml/dialog.cpp
index 241d3b0a..f3432c4b 100644
--- a/osx/dialogxml/dialog.cpp
+++ b/osx/dialogxml/dialog.cpp
@@ -1130,7 +1130,7 @@ bool cDialog::addLabelFor(std::string key, std::string label, eLabelPos where, s
 	labelCtrl->setFormat(TXT_FONT, bold ? SILOM : GENEVA);
 	// TODO: Do we need to set colour to white if background is dark?
 	labelCtrl->setColour(ctrl.getColour());
-	add(labelCtrl, labelRect, key);
+	return add(labelCtrl, labelRect, key);
 }
 
 std::string cDialog::process_keystroke(cKey keyHit){
diff --git a/osx/dialogxml/dialog.h b/osx/dialogxml/dialog.h
index cfb57df6..175f34b2 100644
--- a/osx/dialogxml/dialog.h
+++ b/osx/dialogxml/dialog.h
@@ -41,7 +41,7 @@ class cDialog {
 	void loadFromFile(std::string path);
 public:
 	static void init();
-	static bool noAction(cDialog&,std::string,eKeyMod) {}
+	static bool noAction(cDialog&,std::string,eKeyMod) {return true;}
 	static const short BG_LIGHT, BG_DARK;
 	explicit cDialog(cDialog* p = NULL); // dialog with no items
 	explicit cDialog(std::string path); // cd_create_dialog
diff --git a/osx/dialogxml/pict.cpp b/osx/dialogxml/pict.cpp
index de518b61..750a845b 100644
--- a/osx/dialogxml/pict.cpp
+++ b/osx/dialogxml/pict.cpp
@@ -101,6 +101,7 @@ void cPict::setColour(sf::Color clr) throw(xUnsupportedProp) {
 
 sf::Color cPict::getColour() throw(xUnsupportedProp) {
 	// TODO: Colour is not supported
+	return sf::Color();
 }
 
 void cPict::setPict(pic_num_t num, ePicType type){
diff --git a/osx/dialogxml/scrollbar.cpp b/osx/dialogxml/scrollbar.cpp
index b68eb201..0a23601b 100644
--- a/osx/dialogxml/scrollbar.cpp
+++ b/osx/dialogxml/scrollbar.cpp
@@ -61,6 +61,7 @@ void cScrollbar::setColour(sf::Color clr) throw(xUnsupportedProp) {
 
 sf::Color cScrollbar::getColour() throw(xUnsupportedProp) {
 	// TODO: Colour is unsupported
+	return sf::Color();
 }
 
 void cScrollbar::draw() {
diff --git a/osx/tools/graphtool.cpp b/osx/tools/graphtool.cpp
index eb6b6303..bbcb12df 100644
--- a/osx/tools/graphtool.cpp
+++ b/osx/tools/graphtool.cpp
@@ -877,6 +877,9 @@ public:
 			case 3:
 				return sf::Vector2f(r*sin(t), h + r*cos(t));
 		}
+		// Unreachable
+		printf("Whoops, rounded rectangle had bad point!");
+		return sf::Vector2f();
 	}
 	
 	// TODO: Additional functions?
@@ -1017,6 +1020,7 @@ Region& Region::operator-=(Region& other) {
 		else shape->setFillColor(sf::Color::Black);
 		shapes.push_back(shape);
 	}
+	return *this;
 }
 
 void tileImage(sf::RenderTarget& target, RECT area, sf::Texture& img, sf::BlendMode mode){