(Bastien Montagne already stated this bug in a comment to [#35678], but I am submitting this as a separate bug report because #35678 was closed after the bug stated in the description of #35678 was fixed.)

--- Operating System, Graphics card ---
Windows 7 64-bit Service Pack 1, Mobile Intel 4 Series Express Chipset

--- Blender version with error, and version that worked ---
Error:
* Blender r57476 64-bit (http://builder.blender.org/download/blender-2.67-r57476-win64.zip)
Working: none I know of

--- Short description of error ---
The “show texture in texture tab” button in a modifier does not show up when it should. See the steps below.

--- Steps for others to reproduce the error (preferably based on attached .blend file) ---
1. Open the attachment show-texture-button.blend, or do the following.
1a. Load the factory settings.
1b. Add a Displace modifier to the default Cube object.
1c. In the Modifier tab, click New under label “Texture:” to create a new texture.
2. Observe that the “show texture in texture tab” button is not shown in the Texture field of the Displace modifier.
3. (optional) Switch to the Textures tab, select “Show other data textures” button, and switch back to the Modifiers tab. Observe that the “show texture in texture tab” button is shown now.

The expected behavior is that the “show texture in texture tab” button is shown in step 2 just as in step 3.

Notes:
* This bug is not applicable to Blender 2.67b because it does not have the ability to show modifier textures in the Texture tab when Blender Internal is used.
* The same bug exists also for other modifiers which use textures (cf. the commit log of r57359).