diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index bc107ccfeb..a89080e011 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -1759,8 +1759,6 @@ public:
 		} else if (IsInsideMM(widget, WID_BS_SEMAPHORE_NORM, WID_BS_ELECTRIC_PBS_OWAY + 1)) {
 			size->width = std::max(size->width, this->sig_sprite_size.width + padding.width);
 			size->height = std::max(size->height, this->sig_sprite_size.height + padding.height);
-		} else if (widget == WID_BS_CAPTION) {
-			size->width += WidgetDimensions::scaled.frametext.Horizontal();
 		}
 	}
 
@@ -1879,52 +1877,51 @@ static constexpr NWidgetPart _nested_signal_builder_widgets[] = {
 			NWidget(NWID_VERTICAL, NC_EQUALSIZE),
 				/* Semaphore block signals. */
 				NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
-					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_NORM), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_NORM_TOOLTIP), EndContainer(),
-					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_ENTRY), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_ENTRY_TOOLTIP), EndContainer(),
-					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_EXIT), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_EXIT_TOOLTIP), EndContainer(),
-					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_COMBO), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_COMBO_TOOLTIP), EndContainer(),
+					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_NORM), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_NORM_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
+					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_ENTRY), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_ENTRY_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
+					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_EXIT), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_EXIT_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
+					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_COMBO), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_COMBO_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
 				EndContainer(),
 				/* Electric block signals. */
 				NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
-					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_NORM), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_NORM_TOOLTIP), EndContainer(),
-					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_ENTRY), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_ENTRY_TOOLTIP), EndContainer(),
-					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_EXIT), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_EXIT_TOOLTIP), EndContainer(),
-					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_COMBO), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_COMBO_TOOLTIP), EndContainer(),
+					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_NORM), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_NORM_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
+					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_ENTRY), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_ENTRY_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
+					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_EXIT), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_EXIT_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
+					NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_COMBO), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_COMBO_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
 				EndContainer(),
 			EndContainer(),
 		EndContainer(),
 
 		/* Divider (only shown if block signals visible). */
 		NWidget(NWID_SELECTION, INVALID_COLOUR, WID_BS_BLOCK_SPACER_SEL),
-			NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetMinimalSize(4, 0), EndContainer(),
+			NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetFill(0, 0), SetMinimalSize(4, 0), EndContainer(),
 		EndContainer(),
 
 		/* Path signals. */
 		NWidget(NWID_VERTICAL, NC_EQUALSIZE),
 			/* Semaphore path signals. */
 			NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
-				NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_PBS), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_PBS_TOOLTIP), EndContainer(),
-				NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_PBS_OWAY), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_PBS_OWAY_TOOLTIP), EndContainer(),
+				NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_PBS), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_PBS_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
+				NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_SEMAPHORE_PBS_OWAY), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_SEMAPHORE_PBS_OWAY_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
 			EndContainer(),
 			/* Electric path signals. */
 			NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
-				NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_PBS), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_PBS_TOOLTIP), EndContainer(),
-				NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_PBS_OWAY), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_PBS_OWAY_TOOLTIP), EndContainer(),
+				NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_PBS), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_PBS_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
+				NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BS_ELECTRIC_PBS_OWAY), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_ELECTRIC_PBS_OWAY_TOOLTIP), SetMinimalSize(22, 22), EndContainer(),
 			EndContainer(),
 		EndContainer(),
 
 		/* Convert/autofill buttons. */
 		NWidget(NWID_VERTICAL, NC_EQUALSIZE),
-			NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_BS_CONVERT), SetDataTip(SPR_IMG_SIGNAL_CONVERT, STR_BUILD_SIGNAL_CONVERT_TOOLTIP), SetFill(1, 1),
-			NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_DRAG_SIGNALS_DENSITY_TOOLTIP), SetFill(1, 1),
-				NWidget(WWT_LABEL, COLOUR_DARK_GREEN, WID_BS_DRAG_SIGNALS_DENSITY_LABEL), SetDataTip(STR_JUST_INT, STR_BUILD_SIGNAL_DRAG_SIGNALS_DENSITY_TOOLTIP), SetTextStyle(TC_ORANGE), SetFill(1, 1),
-				NWidget(NWID_HORIZONTAL), SetPIP(2, 0, 2),
-					NWidget(NWID_SPACER), SetFill(1, 0),
-					NWidget(WWT_PUSHARROWBTN, COLOUR_GREY, WID_BS_DRAG_SIGNALS_DENSITY_DECREASE), SetMinimalSize(9, 12), SetDataTip(AWV_DECREASE, STR_BUILD_SIGNAL_DRAG_SIGNALS_DENSITY_DECREASE_TOOLTIP),
-					NWidget(WWT_PUSHARROWBTN, COLOUR_GREY, WID_BS_DRAG_SIGNALS_DENSITY_INCREASE), SetMinimalSize(9, 12), SetDataTip(AWV_INCREASE, STR_BUILD_SIGNAL_DRAG_SIGNALS_DENSITY_INCREASE_TOOLTIP),
-					NWidget(NWID_SPACER), SetFill(1, 0),
+			NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_BS_CONVERT), SetDataTip(SPR_IMG_SIGNAL_CONVERT, STR_BUILD_SIGNAL_CONVERT_TOOLTIP), SetFill(0, 1),
+			NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetDataTip(STR_NULL, STR_BUILD_SIGNAL_DRAG_SIGNALS_DENSITY_TOOLTIP), SetFill(0, 1),
+				NWidget(NWID_VERTICAL), SetPadding(2), SetPIPRatio(1, 0, 1),
+					NWidget(WWT_LABEL, COLOUR_DARK_GREEN, WID_BS_DRAG_SIGNALS_DENSITY_LABEL), SetDataTip(STR_JUST_INT, STR_BUILD_SIGNAL_DRAG_SIGNALS_DENSITY_TOOLTIP), SetTextStyle(TC_ORANGE), SetFill(1, 1),
+					NWidget(NWID_HORIZONTAL), SetPIPRatio(1, 0, 1),
+						NWidget(WWT_PUSHARROWBTN, COLOUR_GREY, WID_BS_DRAG_SIGNALS_DENSITY_DECREASE), SetMinimalSize(9, 12), SetDataTip(AWV_DECREASE, STR_BUILD_SIGNAL_DRAG_SIGNALS_DENSITY_DECREASE_TOOLTIP),
+						NWidget(WWT_PUSHARROWBTN, COLOUR_GREY, WID_BS_DRAG_SIGNALS_DENSITY_INCREASE), SetMinimalSize(9, 12), SetDataTip(AWV_INCREASE, STR_BUILD_SIGNAL_DRAG_SIGNALS_DENSITY_INCREASE_TOOLTIP),
+					EndContainer(),
 				EndContainer(),
-				NWidget(NWID_SPACER), SetMinimalSize(0, 2), SetFill(1, 0),
 			EndContainer(),
 		EndContainer(),
 	EndContainer(),