Thanks!

Is Revision Tracking turned on? No

I exported all 3 userforms and 2 modules, then created a new .DOCM file.


Then I imported all these content to the new DOCM file.
The size at the 1st save decreased from 310kb to 74kb, after using the file, it's grows* to 104kb, but still 1/3 the size of the original file.
* The file just auto save each time it's opened (form queryclose event) a docvariable with len 4 "0000" to save some parameters.
After using a few times, the size now ranges from 79ks to 101kb all (It has now stabilized in 95kb)
I suppose, somehow, it keeps deleted data (especially from excluded controls forms modules, causing this size difference).

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Backup your original file before doing any modification.