Changing drawTexturedModalRect coords has no effect.

I've never seen anything like this before. This code is in GuiIngame.java:

int k = scaledresolution.getScaledWidth();
int l = scaledresolution.getScaledHeight();
/*...*/
if (!this.mc.playerController.enableEverythingIsScrewedUpMode())
    {
        GL11.glColor4f(1.0F, 1.0F, 1.0F, 1.0F);
        this.mc.getTextureManager().bindTexture(widgetsTexPath);
        InventoryPlayer inventoryplayer = this.mc.thePlayer.inventory;
        this.zLevel = -90.0F;
        this.drawTexturedModalRect(k / 2 - 91, l - 22, 0, 0, 182, 22);
        this.drawTexturedModalRect(k / 2 - 91 - 1 + inventoryplayer.currentItem * 20, l - 22 - 1, 0, 22, 24, 22);
        /*...*/
    }

In theory, it renders the hotbar background in the middle of the bottom of the screen. The first two args of  this.drawTexturedModalRect() determine the position on the screen where the hotbar is drawn. I tried changing the coords to this.drawTexturedModalRect(k - 22, l / 2 - 91, 0, 0, 182, 22), but I ended up with this:http://imgur.com/h6rB3bj

In fact, if I comment out these two lines:

//this.drawTexturedModalRect(k / 2 - 91, l - 22, 0, 0, 182, 22);
//this.drawTexturedModalRect(k / 2 - 91 - 1 + inventoryplayer.currentItem * 20, l - 22 - 1, 0, 22, 24, 22);

The hotbar shouldn't render at all, yet it still does! What gives? I know for a fact that changing this code has an effect on vanilla Minecraft. Is there something in Forge that overrides it and makes it unfunctional?