So this is a bit 2 in one i have a gui where i want a custom button, this button needs to fade a bit when i hover over it. But how do i detect if i hover over it? And how do i replace the button? I tried  
 
¨	@Override
public void handleMouseInput() {
	  int mouseX = Mouse.getX();
	  int mouseY = Mouse.getY();
	  if (inRange(this.guiX,this.guiY+2,this.buttonWidth,this.buttonHeight,mouseX,mouseY)){
		  System.out.println("True");
	    }
	  System.out.println(this.guiX+" ; "+this.guiY+2+" ; "+this.buttonWidth+" ; "+this.buttonHeight+" ; "+mouseX+" ; "+mouseY);
	super.handleMouseInput();
}
    
 
  
EDIT:  
Fixed it 
 
int mouseX = Mouse.getEventX() * this.width / this.mc.displayWidth;
         int mouseY = this.height - Mouse.getEventY() * this.height / this.mc.displayHeight - 1;
 
  
Now, how do i replace the already in place button ?  
 
drawTexturedModalRect(guiX, guiY+2, 0, 189, buttonWidth, buttonHeight);