Left Mouse detection doesn't work?

uniform bool bLeftMouseToggle <source="mousebutton"; keycode=0; toggle=true;>;		//Doesn't work
uniform bool bRightMouseToggle <source="mousebutton"; keycode=1; toggle=true;>;		 //Works
uniform bool bMiddleMouseToggle <source="mousebutton"; keycode=2; toggle=true;>;	//Works
uniform bool bMouse4Toggle <source="mousebutton"; keycode=3; toggle=true;>;		//Works
uniform bool bMouse5Toggle <source="mousebutton"; keycode=4; toggle=true;>;		//Works

float4 TestPS(float4 pos : SV_Position, float2 uv : TEXCOORD) : SV_Target {	
	float3 currentColor;
	if( bLeftMouseToggle ){
		currentColor = float3(1.0, 0.0, 0.0); //Red
	} else if( bRightMouseToggle ){
		currentColor = float3(0.0, 1.0, 0.0); //Green
	} else if( bMiddleMouseToggle ){
		currentColor = float3(0.0, 0.0, 1.0); //Blue
	} else if( bMouse4Toggle ){
		currentColor = float3(0.0, 1.0, 1.0); //Cyan
	} else if( bMouse5Toggle ){
		currentColor = float3(1.0, 0.0, 1.0); //Magenta
	}
	return float4(currentColor, 1.0);
}