ActiveX warning message despite allowing all ActiveX in Trust Center

[vmser]

I have an issue I'm struggling with, and it bothers me to no end. However, I can't come up with a decent solution, so I'm turning to you folks for advice.

The problem is as follows:
I have a .xlsm file containing a few macros. The macros use Forms, and specifically they also use TreeView objects in them (through mscomctl.ocx). I have gone through the Trust Center, and set every setting to it's unsafest form (allow all ActiveX, allow all VBA, no 'safe mode' for web documents, etc etc...

I can open the file, but when I call the macro relying on forms, I get a warning message labeled 'Microsoft Forms', with the following error message:

This application is about to initialize ActiveX Controls that might be
unsafe. If you trust the source of this document, select Yes and the
control will be initialized using your document settings.

It both surprises me (I said to allow it all in the settings, didn't I?) and annoys me (well, not the first time, but me and my coworkers use it on a daily basis and it gets on my nerves).

Does anyone have a clue whatsoever as to:
1) Why this happens?
2) How I can avoid the message?

I'm open to both solutions on altering the Excel file, or settings I have to alter on local machines (<20 PC's).

Details:
Windows 8.1, running Excel 2013.
The macro-code is 'safe', it's built by our company employees (myself included). Code is password-protected so can't be meddled with.

 

[CalcSux78]

I don't think I've encountered that one, but have you tried wrapping the call with:

Application.DisplayAlerts = False
Call Macro1
Application.DisplayAlerts = True

 

[vmser]

I don't think I've encountered that one, but have you tried wrapping the call with:

Application.DisplayAlerts = False
Call Macro1
Application.DisplayAlerts = True

Here's the thing: I try to avoid toggling off 'DisplayAlerts' to the best of my abilities. We've had issues that if a macro crashes, it remains 'stuck' in its toggled off state.
Somehow (beyond me) it implies that sometimes when you try and alter a cell, it doesn't appear to change in the worksheet shown, but in one of the hidden sheets at that position.

Needless to say: That's something I want to avoid.

 

[RoryA]

I think you need to edit the registry: https://support.microsoft.com/en-us/kb/827742

 

[vmser]

I think you need to edit the registry: https://support.microsoft.com/en-us/kb/827742

That only references Office 2003 and Office XP.
I'm having the issue with Office 2013, and with an .xlsm file.

As for the Registry:
UFIControls was already set to '1' (which should be the best setting for my case?)
LoadControlsInForms (matching 'Forms3') was not found in registry.

 

[RoryA]

Do you have the equivalent mentioned Policies or HKLM entries that might be overriding your settings?

 

[vmser]

Do you have the equivalent mentioned Policies or HKLM entries that might be overriding your settings?

I have no other entries in the registry with the same name.

PS: I've tried the same file on an old windows XP pc, with office 2003 - and I do NOT get the error.
Any pointers on how I can make the file 'SFI'?

 

[mole999]

Daft idea, is it possible to record a macro that enables the activex, and embed that in the file on open? (though that doesn't appear possible)

I expect you have read > https://technet.microsoft.com/en-gb/library/cc179076.aspx

Not sure how MS could flag mscomctl.ocx as unsafe, is it the correct version, maybe > https://support.microsoft.com/en-us/kb/896559