I see waveseekbar no longer processes the next song in the list - I listen to a song (10-20 seconds so WS has the time to process the next song), and then advance to the next song, and I see the delay until WS processes it and shows its wave. Why this change, or it is a bug? I'm sorry, I went through the last few pages but I don't seem to find anything related.

texture tex : WAVEFORMDATA;

sampler sTex = sampler_state
{
	Texture = (tex);
	MipFilter = LINEAR;
	MinFilter = LINEAR;
	MagFilter = LINEAR;
	
	AddressU = Clamp;
};

struct VS_IN
{
	float2 pos : POSITION;
	float2 tc : TEXCOORD0;
};

struct PS_IN
{
	float4 pos : SV_POSITION;
	float2 tc : TEXCOORD0;
};


float4 backgroundColor : BACKGROUNDCOLOR;
float4 highlightColor  : HIGHLIGHTCOLOR;
float4 selectionColor  : SELECTIONCOLOR;
float4 textColor       : TEXTCOLOR;
float cursorPos        : CURSORPOSITION;
bool cursorVisible     : CURSORVISIBLE;
float seekPos          : SEEKPOSITION;
bool seeking           : SEEKING;
float4 replayGain      : REPLAYGAIN; // album gain, track gain, album peak, track peak
float2 viewportSize    : VIEWPORTSIZE;
bool horizontal        : ORIENTATION;
bool flipped           : FLIPPED;
bool shade_played      : SHADEPLAYED;
float3 track_magnitude  : TRACKMAGNITUDE;

PS_IN VS( VS_IN input )
{
	PS_IN output = (PS_IN)0;

	float2 half_pixel = float2(1,-1) / viewportSize;
	output.pos = float4(input.pos - half_pixel, 0, 1);

	if (horizontal)
		output.tc = float2((input.tc.x + 1.0) / 2.0, input.tc.y);
	else
		output.tc = float2((-input.tc.y + 1.0) / 2.0, input.tc.x);

	if (flipped)
		output.tc.x = 1.0 - output.tc.x;

	return output;
}

float4 bar( float pos, float2 tc, float4 fg, float4 bg, float width, bool show )
{
	float dist = abs(pos - tc.x);
	float4 c = (show && dist < width)
		? lerp(fg, bg, smoothstep(0, width, dist))
		: bg;
	return c;
}

float4 evaluate( float2 tc, float cursorPos )
{
	// alpha 1 indicates biased texture
	float4 minmaxrms = tex1D(sTex, tc.x);
	minmaxrms.rgb -= 0.5 * minmaxrms.a;
	minmaxrms.rgb *= 1.0 + minmaxrms.a;
	float below = tc.y - minmaxrms.r;
	float above = tc.y - minmaxrms.g;
	float factor = min(abs(below), abs(above));
	bool outside = (below < 0 || above > 0);
	bool inside_rms = abs(tc.y) <= minmaxrms.b;
	bool played = cursorPos < tc.x;
	float4 inside_color = played ? textColor : highlightColor;
	float4 bgColor = backgroundColor;

	float4 wave = outside
		? bgColor
		: inside_color
		;

	return saturate(wave);
}

float4 reflect_evaluate( float2 tc, float cursorPos)
{
	float baseline = -1.0/3.0;
	float low_unscale = 3.0/2.0;
	float high_unscale = 3.0/4.0;
	bool mirrored = tc.y < baseline;
	if (mirrored) {
		tc.y = baseline - tc.y;
		tc.y = tc.y * low_unscale;
	}
	else {
		tc.y = tc.y - baseline;
		tc.y = tc.y * high_unscale;
	}
	float mag = max(-track_magnitude.r, track_magnitude.g);
	if (mag > 0.95) {
		tc.y = lerp(0, mag/0.95, tc.y);
	}
	float boost = mirrored ? 1.3 : 1.0;
	float gradient = lerp(0.7, 1.0, tc.y);
	return boost * gradient * evaluate(tc, cursorPos);
}

float4 PS( PS_IN input ) : SV_Target
{
	float dx, dy;
	if (horizontal) {
		dx = 1/viewportSize.x;
		dy = 1/viewportSize.y;
	}
	else {
		dx = 1/viewportSize.y;
		dy = 1/viewportSize.x;
	}
	float seekWidth = 2.5 * dx;
	float positionWidth = 2.5 * dx;

	float4 c0 = reflect_evaluate(input.tc, cursorPos);
	c0 = bar(cursorPos, input.tc, selectionColor, c0, positionWidth, cursorVisible);
	c0 = bar(seekPos,   input.tc, selectionColor, c0, seekWidth,     seeking      );
	return c0;
}

technique Render9
{
	pass
	{
		VertexShader = compile vs_2_0 VS();
		PixelShader = compile ps_2_0 PS();
	}
}