Ticket #3208: Wall additions can not be set to auto (floor height).

[Kunda1]

issue #3208: Wall additions can not be set to auto (floor height).

Description
When a wall is composed of additions and placed in a floor... the hight of the composed wall can be set to automatic (i.e. resulting in the floor's height). However, this does not carry through to the additions. While the additions' heights can be altered, when set to automatic and recomputed, they remain whatever they were last at.

I recommend that when a a parent wall is changed it doesn't automatically change the child's, (because internal wall may intentionally be unique) - however, the children should at least be allowed to be set to automatic as well.


Steps To Reproduce
1. Create multiple walls
2. Merge walls by adding to a parent (plus sign) [not sure about MergeWalls()]
3. Place in a floor
4. Set parent wall's height to '0'
5. Modify floor height (note only parent wall changes)
6. Modify child wall (note change)
7. Set child wall to '0' (not no change)

Additional Information
OS: Ubuntu 17.04
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.12289 (Git)
Build type: None
Branch: master
Hash: 53168d39d6ea03a21f38337363ae0669f1f31507
Python version: 2.7.13
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: English/UnitedStates (en_US)

[Kunda1]

Related: https://forum.freecadweb.org/viewtopic.php?f=3&t=39302