diff --git a/share/man/man4/hidquirk.4 b/share/man/man4/hidquirk.4
index aa78e189765c..cbe0e33c934c 100644
--- a/share/man/man4/hidquirk.4
+++ b/share/man/man4/hidquirk.4
@@ -53,6 +53,8 @@ doesn't identify properly
 mouse sends an unknown leading byte
 .It HQ_MS_REVZ
 mouse has Z-axis reversed
+.It HQ_MS_VENDOR_BTN
+mouse has buttons in vendor usage page
 .It HQ_SPUR_BUT_UP
 spurious mouse button up events
 .It HQ_MT_TIMESTAMP
diff --git a/sys/dev/hid/hidquirk.c b/sys/dev/hid/hidquirk.c
index 7c28e240582b..dfb97a3e5597 100644
--- a/sys/dev/hid/hidquirk.c
+++ b/sys/dev/hid/hidquirk.c
@@ -151,6 +151,8 @@ static struct hidquirk_entry hidquirks[HID_DEV_QUIRKS_MAX] = {
 	USB_QUIRK(CORSAIR, STRAFE2, 0x0000, 0xffff, HQ_KBD_BOOTPROTO),
 	/* Holtek USB gaming keyboard */
 	USB_QUIRK(HOLTEK, F85, 0x0000, 0xffff, HQ_KBD_BOOTPROTO),
+	/* Quirk for Kensington Slimblade Trackball */
+	USB_QUIRK(KENSINGTON, SLIMBLADE, 0x0000, 0xffff, HQ_MS_VENDOR_BTN),
 };
 #undef HID_QUIRK_VP
 #undef USB_QUIRK
diff --git a/sys/dev/hid/hidquirk.h b/sys/dev/hid/hidquirk.h
index 0201f2f0746c..5f0dafb8a8a2 100644
--- a/sys/dev/hid/hidquirk.h
+++ b/sys/dev/hid/hidquirk.h
@@ -59,6 +59,7 @@
 	HQ(MS_BAD_CLASS),	/* doesn't identify properly */		\
 	HQ(MS_LEADING_BYTE),	/* mouse sends an unknown leading byte */ \
 	HQ(MS_REVZ),		/* mouse has Z-axis reversed */		\
+	HQ(MS_VENDOR_BTN),	/* mouse has buttons in vendor usage page */ \
 	HQ(SPUR_BUT_UP),	/* spurious mouse button up events */	\
 	HQ(MT_TIMESTAMP)	/* Multitouch device exports HW timestamps */
 
diff --git a/sys/dev/hid/hms.c b/sys/dev/hid/hms.c
index b1580c3db358..87d207cc3f6b 100644
--- a/sys/dev/hid/hms.c
+++ b/sys/dev/hid/hms.c
@@ -61,8 +61,6 @@ enum {
 	HMS_ABS_Z,
 	HMS_HWHEEL,
 	HMS_BTN,
-	HMS_BTN_MS1,
-	HMS_BTN_MS2,
 	HMS_FINAL_CB,
 };
 
@@ -95,8 +93,6 @@ static const struct hidmap_item hms_map[] = {
 	[HMS_ABS_Z]	= HMS_MAP_ABS(HUG_Z,		ABS_Z),
 	[HMS_HWHEEL]	= HMS_MAP_REL_CN(HUC_AC_PAN,	REL_HWHEEL),
 	[HMS_BTN]	= HMS_MAP_BUT_RG(1, 16,		BTN_MOUSE),
-	[HMS_BTN_MS1]	= HMS_MAP_BUT_MS(1,		BTN_RIGHT),
-	[HMS_BTN_MS2]	= HMS_MAP_BUT_MS(2,		BTN_MIDDLE),
 	[HMS_FINAL_CB]	= HMS_FINAL_CB(hms_final_cb),
 };
 
@@ -107,6 +103,11 @@ static const struct hidmap_item hms_map_wheel_rev[] = {
 	HMS_MAP_REL_REV(HUG_WHEEL,	REL_WHEEL),
 };
 
+static const struct hidmap_item hms_map_kensington_slimblade[] = {
+	HMS_MAP_BUT_MS(1,	BTN_RIGHT),
+	HMS_MAP_BUT_MS(2,	BTN_MIDDLE),
+};
+
 /* A match on these entries will load hms */
 static const struct hid_device_id hms_devs[] = {
 	{ HID_TLC(HUP_GENERIC_DESKTOP, HUG_POINTER) },
@@ -261,6 +262,9 @@ hms_attach(device_t dev)
 	else
 		HIDMAP_ADD_MAP(&sc->hm, hms_map_wheel, cap_wheel);
 
+	if (hid_test_quirk(hw, HQ_MS_VENDOR_BTN))
+		HIDMAP_ADD_MAP(&sc->hm, hms_map_kensington_slimblade, NULL);
+
 #ifdef IICHID_SAMPLING
 	if (hid_test_quirk(hw, HQ_IICHID_SAMPLING) &&
 	    hidmap_test_cap(sc->caps, HMS_REL_X) &&