Step one:
Create a new transparent blank document. Set foreground color to white. Select the Shapes tool and choose Polygon. On the shapes toolbar, create a rasterized shape by clicking on the third square. Type in 6 in the sides box to make it a six sided polygon. Hold the shift key and draw the shape on your blank document.

Step two:
Select the rectangle marquee and draw a rectangle over the bottom half of the polygon. Hit the delete key and CTRL + D to deselect. Go to the Layers palette and CTRL + CLICK to select your shape. Go to the SELECT menu and save selection. Name it "Alpha"

Step three:
Click on the Channels palette and choose the Alpha channel and deselect the layer. Go to filters, blur, Gaussian blur and set the radius to 10. Click Ok. CTRL + F to apply the filter twice more

Step four:
Press CTRL + L to open the levels dialogue box. In the Levels dialogue box move the sliders so that they touch in the center or type in the input levels 120 Black, 1 Gray and 145 White. Click OK.

Step five:
In the channels Palette CTRL + Click the Alpha Channel to select it. Click on the Layers Palette and and click on Layer 1. Go to the Select menu and choose Inverse (SHIFT + CTRL + I) Hit the delete key and then Deselect the Layer (CTRL + D)

Step six:
Now you have a rounded tab that you can resize and change the color to suit your needs!