I can confirm that for BI and Cycles in Textured mode (compared to 2.76b):

• Blender Internal: vertex colors are not showing in Object, Sculpt and Vertex Paint modes, but are shown in Edit Mode.
• Cycles: Vertex colors are not showing in Object, Sculpt and Edit Modes, but are shown in Vertex Paint mode with proper gradients. I have noticed that in Material view vertex colors look differrently from other modes (sRGB space?) This heavily affects gradients from vertex to vertex, making them very pale.

Haven't noticed anything suspicious in the console so far.

Sorry if I wasn't clear enough, but that's what I see when I'm switching interaction modes in Textured viewport shading. Probably should have added pictures in the first place. The planes on these pictures are the same object in different modes.

In T48728#379369, @Bastien Montagne (mont29) wrote:

This 'feature' was purposely removed from master a few weeks ago (by @Campbell Barton (campbellbarton) iirc) - it did not really make sense to systematically show vcol in texture paint mode, and was actually often annoying.

@Bastien Montagne (mont29) it doesn't make sense for me now since texture applied to uvs without material are instead correctly displayed. Vertex colors have no different use in that case but are displayed as a blank white shadeless object (not very useful at all).

In T48728#379369, @Bastien Montagne (mont29) wrote:

You can still see those if you enable vcols in your material and switch to material preview mode.

@Bastien Montagne (mont29) yeah, i could, but in a complex scene where lots materials are linked, you are suggesting to let blender viewport compute all of them (affecting severely the performance) when the only thing i have to see are the vertex colors. I don't think it's very handy. And i can't honestly see the benefit of removing this feature and make textures and vcols (both used to color the object) behave differently in the viewport.

Actually, was @Sergey Sharybin (sergey) 's commit, rB03f846ea.

If it's really supposed to show vertex color in textured view simplest way to go would be to add DM_DRAW_USE_COLORS to flags in draw_mesh_textured_old() in cases when object is not in texture paint mode.

But my question is: is it indeed supposed to always use vertex color in texture view?

In T48728#379802, @Sergey Sharybin (sergey) wrote:

But my question is: is it indeed supposed to always use vertex color in texture view?

@Sergey Sharybin (sergey), my point is: if you are using vertex colors to color your object, then they have to be shown in texture mode just as you would expect using a texture to color the object.
No material is required to show a texture, and no material should be needed to show the vcols.
If you are not using vertex colors, no harm could be done because they would not be shown anyway.
This is also rhe way it was always used in the blender viewport.
If the removal is so important, then at least a flag in the view 3D has to be present to show them. Again, my point is: what's the benefit of remiving it from the viewport itself breaking existing workflow when the problem is only affecting the texture paint mode?

I'm not sure if I understood the question correctly, but as far as I can understand, it boils down to what to display in Object and Sculpt modes when Diffuse color, image texture and vertex colors are presented.

I did some tests in 2.77a in Textured Solid Object mode and it work like this:

• Material's Diffuse color when no image or vertex colors are presented
• Vertex colors when image is not directly assigned to faces in Edit Mode
• Image multiplied by vertex colors when image is directly assigned to faces in Edit Mode
• Image multiplied by vertex colors in Vertex Paint mode when image is directly assigned to faces in Edit Mode
• Image in Texture Paint mode which is multiplied by vertex colors when "Face selection masking for painting" is turned on.

I can understand how it can cause problems so maybe it would be possible to do this:

• Material's Diffuse color when no image or vertex colors are presented
• Vertex colors only when image is not directly assigned to faces in Edit Mode
• Image only when image is directly assigned to faces in Edit Mode
• Only vertex colors in Vertex Paint mode
• Only image in Texture Paint mode regardless of "Face selection masking for painting" option.

This is obviously not an ideal solution and can be counterintuitive, but at least it will separate image and vertex colors and we won't lose the ability to see vertex colors in Textured Solid modes. I'm not sure if that makes sense so this is just my thoughts.

I've just tested the latest build 9d5661c and it looks like the problem wasn't solved completely: object's diffuse color is now updating properly, but both diffuse color and vertex colors are only shown when object is actively selected. If many objects are selected, only the active one will display colors properly, others will show plain gray.

1. Create a Cube and add material with Diffuse color or paint some vertices in vertex paint mode.
2. Switch to Texture shading and add another primitive or select another object (for example default lamp or camera) and object will turn gray.

Tested 4b0aeaf and most combinations of modes work normally except strange behaviour in Sculpting mode which doesn't update material’s diffuse color properly:

1. Set some vivid color to default Cube's material diffuse color and turn Textured Solid mode.
2. If you switch to Sculpting mode right away, diffuse color will remain, but if you switch to Edit Mode and then to Sculpt mode, in Sculpt mode object’s color will become gray. Switching to Object mode and then back to Sculpt mode will bring diffuse color back.
3. I have also noticed that if you'll try to change diffuse color while in Sculpt mode, it will not update just like in previous versions.

Just in case my previous report was lost in a traffic: tested b27322e and Diffuse color in Sculpting mode is still not updating properly in BI Textured Solid mode. Not a big problem perhaps, but can be quite annoying because you have to switch back and forth between Sculpt and Object mode to see Diffuse color update.

@Alex (SpectreFirst), this is why it is important to create mew reports instead of re-summoning old ones. So please go ahead and submit a new report with the steps and probably .blend file.