Index: src/rail_gui.cpp
===================================================================
--- src/rail_gui.cpp	(revision 17180)
+++ src/rail_gui.cpp	(working copy)
@@ -314,7 +314,7 @@
 
 /** Updates the Remove button because of Ctrl state change
  * @param w window the button belongs to
- * @return true iff the remove buton was changed
+ * @return true if the remove button was changed
  */
 static bool RailToolbar_CtrlChanged(Window *w)
 {
@@ -1536,7 +1536,13 @@
 
 	virtual void OnPaint()
 	{
-		this->LowerWidget((_cur_signal_variant == SIG_ELECTRIC ? BSW_ELECTRIC_NORM : BSW_SEMAPHORE_NORM) + _cur_signal_type);
+		/* Only lower the currently selected widget if none has been lowered yet.
+		 * This way widgets can be modified without changing _cur_signal_variant
+		 */
+		if (!this->IsWidgetLowered(BSW_ELECTRIC_NORM + _cur_signal_type) && !this->IsWidgetLowered(BSW_SEMAPHORE_NORM + _cur_signal_type)) {
+			this->LowerWidget(((_cur_signal_variant == SIG_ELECTRIC) ? BSW_ELECTRIC_NORM : BSW_SEMAPHORE_NORM) + _cur_signal_type);
+			if (_ctrl_pressed) OnCTRLStateChange(); // when a button is ctrl-clicked
+		}
 
 		this->SetWidgetLoweredState(BSW_CONVERT, _convert_signal_button);
 
@@ -1581,7 +1587,7 @@
 			case BSW_ELECTRIC_COMBO:
 			case BSW_ELECTRIC_PBS:
 			case BSW_ELECTRIC_PBS_OWAY:
-				this->RaiseWidget((_cur_signal_variant == SIG_ELECTRIC ? BSW_ELECTRIC_NORM : BSW_SEMAPHORE_NORM) + _cur_signal_type);
+				this->RaiseWidget((this->IsWidgetLowered(BSW_ELECTRIC_NORM + _cur_signal_type) ? BSW_ELECTRIC_NORM : BSW_SEMAPHORE_NORM) + _cur_signal_type);
 
 				_cur_signal_type = (SignalType)((uint)((widget - BSW_SEMAPHORE_NORM) % (SIGTYPE_LAST + 1)));
 				_cur_signal_variant = widget >= BSW_ELECTRIC_NORM ? SIG_ELECTRIC : SIG_SEMAPHORE;
@@ -1589,6 +1595,10 @@
 
 			case BSW_CONVERT:
 				_convert_signal_button = !_convert_signal_button;
+				if (_convert_signal_button && _ctrl_pressed) {
+					this->RaiseWidget((this->IsWidgetLowered(BSW_ELECTRIC_NORM + _cur_signal_type)
+						? BSW_ELECTRIC_NORM : BSW_SEMAPHORE_NORM) + _cur_signal_type);
+				}
 				break;
 
 			case BSW_DRAG_SIGNALS_DENSITY_DECREASE:
@@ -1610,6 +1620,22 @@
 
 		this->SetDirty();
 	}
+
+	virtual EventState OnCTRLStateChange()
+	{
+		/* One of the button states needs to be stored, otherwise both button variants end up in the same state. */
+		bool electric_lowered = this->IsWidgetLowered(BSW_ELECTRIC_NORM + _cur_signal_type);
+		/* Using the signal converter with ctrl doesn't depend on selected signal,
+		 * so it's clearer to raise the selected signal button for the duration of ctrl-press. */
+		if (_convert_signal_button && _ctrl_pressed) {
+			this->RaiseWidget((electric_lowered ? BSW_ELECTRIC_NORM : BSW_SEMAPHORE_NORM) + _cur_signal_type);
+		} else {
+			this->SetWidgetLoweredState(BSW_ELECTRIC_NORM + _cur_signal_type, (this->IsWidgetLowered(BSW_SEMAPHORE_NORM + _cur_signal_type)) ? 1 : 0);
+			this->SetWidgetLoweredState(BSW_SEMAPHORE_NORM + _cur_signal_type, electric_lowered ? 1 : 0);
+		}
+		this->SetDirty();
+		return ES_NOT_HANDLED;
+	}
 };
 
 /** Nested widget definition of the build signal window */