diff --git a/src/app.cpp b/src/app.cpp
index d44ad82..2381e78 100644
--- a/src/app.cpp
+++ b/src/app.cpp
@@ -11,6 +11,7 @@ App::App()
 	InitOVR();
 	InitX11();
 	InitGLFW();
+	printf("\n");
 
 	glGenTextures(1, &_gl_frame);
 	glBindTexture(GL_TEXTURE_2D, _gl_frame);
@@ -124,6 +125,15 @@ glm::mat4 App::GetTrackerPose(TrackerID tracker)
 	return ConvertMat(tracked_pose.mDeviceToAbsoluteTracking);
 }
 
+vr::VRControllerState_t App::GetControllerState(TrackerID controller)
+{
+	vr::VRControllerState_t state;
+	auto get_state_err = vr_sys->GetControllerState(controller, &state, sizeof(vr::VRControllerState_t));
+	if (get_state_err == false)
+		printf("failed to get state of controller %d\n", controller);
+	return state;
+}
+
 bool App::IsGrabActive(TrackerID controller)
 {
 	vr::VRControllerState_t state;
@@ -132,9 +142,7 @@ bool App::IsGrabActive(TrackerID controller)
 		return false;
 
 	auto trigger_mask = vr::ButtonMaskFromId(vr::k_EButton_SteamVR_Trigger);
-	auto b_mask = vr::ButtonMaskFromId(vr::k_EButton_IndexController_B);
-	auto mask = trigger_mask | b_mask;
-	return (state.ulButtonPressed & mask) == mask;
+	return state.ulButtonPressed & trigger_mask;
 }
 
 CursorPos App::GetCursorPosition()
diff --git a/src/app.h b/src/app.h
index 373a499..d881b2e 100644
--- a/src/app.h
+++ b/src/app.h
@@ -20,6 +20,7 @@ class App
 
 	std::vector<TrackerID> GetControllers();
 	glm::mat4 GetTrackerPose(TrackerID tracker);
+	vr::VRControllerState_t GetControllerState(TrackerID controller);
 	bool IsGrabActive(TrackerID controller);
 	CursorPos GetCursorPosition();
 
diff --git a/src/panel.cpp b/src/panel.cpp
index 0eb07bc..ce2a910 100644
--- a/src/panel.cpp
+++ b/src/panel.cpp
@@ -3,6 +3,7 @@
 #include "util.h"
 
 #include <X11/Xutil.h>
+#include <glm/common.hpp>
 #include <glm/glm.hpp>
 
 Panel::Panel(App *app, vr::HmdMatrix34_t start_pose, int index, int x, int y, int width, int height)
@@ -82,6 +83,15 @@ void Panel::Update()
 		{
 			ControllerRelease();
 		}
+		auto state = _app->GetControllerState(_active_hand);
+		auto touchpad = state.rAxis[0];
+		if (touchpad.x != 0.0f)
+		{
+			// TODO take into account the current framerate
+			_alpha += touchpad.x * 0.05;
+			_alpha = glm::clamp(_alpha, 0.1f, 1.0f);
+			_app->vr_overlay->SetOverlayAlpha(_id, _alpha);
+		}
 	}
 }