From a2567fcac9851e5cc965a236679f568b0e79cff2 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Mon, 17 Jun 2024 09:28:40 -0400
Subject: [PATCH] devdraw: handle shift of real mouse buttons correctly

---
 src/cmd/devdraw/mac-screen.m | 10 +++++-----
 src/cmd/devdraw/x11-screen.c | 23 ++++++++++++++++++-----
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/cmd/devdraw/mac-screen.m b/src/cmd/devdraw/mac-screen.m
index 04c807b7a..6abdee113 100644
--- a/src/cmd/devdraw/mac-screen.m
+++ b/src/cmd/devdraw/mac-screen.m
@@ -639,9 +639,9 @@ - (void)flagsChanged:(NSEvent*)e
 			x = 2;
 		if(m & ~omod & NSEventModifierFlagCommand)
 			x = 4;
-		if(m & NSEventModifierFlagShift)
-			x <<= 5;
 		b |= x;
+		if(m & NSEventModifierFlagShift)
+			b <<= 5;
 		[self sendmouse:b];
 	}else if(m & ~omod & NSEventModifierFlagOption)
 		gfx_keystroke(self.client, Kalt);
@@ -698,17 +698,17 @@ - (void)getmouse:(NSEvent *)e
 	b = b&~6 | (b&4)>>1 | (b&2)<<1;
 	b = mouseswap(b);
 
+	m = [e modifierFlags];
 	if(b == 1){
-		m = [e modifierFlags];
 		if(m & NSEventModifierFlagOption){
 			gfx_abortcompose(self.client);
 			b = 2;
 		}else
 		if(m & NSEventModifierFlagCommand)
 			b = 4;
-		if(m & NSEventModifierFlagShift)
-			b <<= 5;
 	}
+	if(m & NSEventModifierFlagShift)
+		b <<= 5;
 	[self sendmouse:b];
 }
 
diff --git a/src/cmd/devdraw/x11-screen.c b/src/cmd/devdraw/x11-screen.c
index 9490ab8f2..f4aa1ce9e 100644
--- a/src/cmd/devdraw/x11-screen.c
+++ b/src/cmd/devdraw/x11-screen.c
@@ -376,6 +376,7 @@ runxevent(XEvent *xev)
 	if(w == nil)
 		w = _x.windows;
 
+	int shift;
 	switch(xev->type){
 	case Expose:
 		_xexpose(w, xev);
@@ -406,7 +407,10 @@ runxevent(XEvent *xev)
 	case MotionNotify:
 		if(_xtoplan9mouse(w, xev, &m) < 0)
 			return;
-		gfx_mousetrack(w->client, m.xy.x, m.xy.y, m.buttons|_x.kbuttons, m.msec);
+		shift = 0;
+		if(_x.kstate & ShiftMask)
+			shift = 5;
+		gfx_mousetrack(w->client, m.xy.x, m.xy.y, (m.buttons|_x.kbuttons)<<shift, m.msec);
 		break;
 
 	case KeyRelease:
@@ -440,32 +444,41 @@ runxevent(XEvent *xev)
 			case XK_Alt_L:
 			case XK_Alt_R:
 				kcodealt = ke->keycode;
-				// fall through
+				c |= Mod1Mask;
+				modp = 1;
+				break;
 			case XK_Shift_L:
 			case XK_Shift_R:
 				kcodeshift = ke->keycode;
-				c |= Mod1Mask;
+				c |= ShiftMask;
 				modp = 1;
+				break;
 			}
 		else {
 			if(ke->keycode == kcodecontrol){
 				c &= ~ControlMask;
 				modp = 1;
-		        } else if(ke->keycode == kcodealt || ke->keycode == kcodeshift){
+		        } else if(ke->keycode == kcodealt){
 				c &= ~Mod1Mask;
 				modp = 1;
+			} else if(ke->keycode == kcodeshift) {
+				c &= ~ShiftMask;
+				modp = 1;
 			}
 		}
 		if(modp){
 			_x.kstate = c;
 			if(m.buttons || _x.kbuttons) {
+				int shift = 0;
 				_x.altdown = 0; // used alt
 				_x.kbuttons = 0;
 				if(c & ControlMask)
 					_x.kbuttons |= 2;
 				if(c & Mod1Mask)
 					_x.kbuttons |= 4;
-				gfx_mousetrack(w->client, m.xy.x, m.xy.y, m.buttons|_x.kbuttons, m.msec);
+				if(c & ShiftMask)
+					shift = 5;
+				gfx_mousetrack(w->client, m.xy.x, m.xy.y, (m.buttons|_x.kbuttons)<<shift, m.msec);
 			}
 			modp = 0;
 		}