(In reply to Becoming DAU from comment #0)
> When choosing "right indent" for numbers in cells, the field for the value
> get greyed out.
> 
> But if there is already a value there (e.g. by selecting left indent before)
> this is used for the indent after pressing "OK". In other words the value
> for "right indent" can only be changed while "left indent" is selected.

Where can I select this "right indent" or "left indent"?

Set to NEEDINFO.
Change back to UNCONFIRMED after you have provided the information.

Created attachment 116418 [details]
Format Cells - Text Alignment

While choosing right for the horizontal alignment inside the cells the indent is greyed out and therefore cannot be changed.
But when the indent is set while left alignment is chosen, I can later change it to right alignment with the before set indent (which is shown greyed out in the indent field).

You were right (pun indented) :)

Win 7 Pro 64-bit Version: 5.1.0.0.alpha1+
Build ID: 698b344fdf42cc9738d5e91cd27876ce1ff39daf
TinderBox: Win-x86@39, Branch:master, Time: 2015-06-10_02:24:19
Locale: fi-FI (fi_FI)

Version: 6.3.6.2 (x64)
Build ID: 2196df99b074d8a661f4036fca8fa0cbfa33a497
CPU threads: 4; OS: Windows 10.0; UI render: default; VCL: win; 
Locale: sv-SE (en_GB); UI-Language: en-GB
Calc: threaded

Still occurring  for me

(In reply to Colin from comment #6)
> Version: 6.3.6.2 (x64)
> Build ID: 2196df99b074d8a661f4036fca8fa0cbfa33a497
> CPU threads: 4; OS: Windows 10.0; UI render: default; VCL: win; 
> Locale: sv-SE (en_GB); UI-Language: en-GB
> Calc: threaded
> 
> Still occurring  for me

Furthermore, if the cell is formatted for word wrap and the wrap is active, then when the left indent default is retained for a right indent it forces the cell into overflow with just a single word visible on each line. If the cell is then reverted to left indent the overflow is left biased but loses most of the content to overflow.

Let me know if an example is required but the procedure is as simple as 
1 create data too large for a cell
2 apply left alignment NOT default as this will not permit indent definition
3 apply 3 point indent
4 apply word wrap
5 redefine left align to right align
6 Observe anomaly
7 Revert to left align
8 Observe anomaly

(In reply to Colin from comment #7)
> (In reply to Colin from comment #6)
> > Version: 6.3.6.2 (x64)
> > Build ID: 2196df99b074d8a661f4036fca8fa0cbfa33a497
> > CPU threads: 4; OS: Windows 10.0; UI render: default; VCL: win; 
> > Locale: sv-SE (en_GB); UI-Language: en-GB
> > Calc: threaded
> > 
> > Still occurring  for me
> 
> Furthermore, if the cell is formatted for word wrap and the wrap is active,
> then when the left indent default is retained for a right indent it forces
> the cell into overflow with just a single word visible on each line. If the
> cell is then reverted to left indent the overflow is left biased but loses
> most of the content to overflow.
> 
> Let me know if an example is required but the procedure is as simple as 
> 1 create data too large for a cell
> 2 apply left alignment NOT default as this will not permit indent definition
> 3 apply 3 point indent
> 4 apply word wrap
> 5 redefine left align to right align
> 6 Observe anomaly
> 7 Revert to left align
> 8 Observe anomaly

It gets better. If two colimns are present and the left right formatting exercise is performed on the right cells it works as above
If the left cells are then formatted left/right it "wipes out" the formatting to the right cells and will not recognise further formatting endeavours to those cells.

My apologies for "chopping and changing" my comment - not sure whether the protocol is to keep filing new comments as my appreciation of the error's impact develops or append to my original comment as everything is as yet unaddressed.

(In reply to Colin from comment #8)
> (In reply to Colin from comment #7)
> > (In reply to Colin from comment #6)
> > > Version: 6.3.6.2 (x64)
> > > Build ID: 2196df99b074d8a661f4036fca8fa0cbfa33a497
> > > CPU threads: 4; OS: Windows 10.0; UI render: default; VCL: win; 
> > > Locale: sv-SE (en_GB); UI-Language: en-GB
> > > Calc: threaded
> > > 
> > > Still occurring  for me
> > 
> > Furthermore, if the cell is formatted for word wrap and the wrap is active,
> > then when the left indent default is retained for a right indent it forces
> > the cell into overflow with just a single word visible on each line. If the
> > cell is then reverted to left indent the overflow is left biased but loses
> > most of the content to overflow.
> > 
> > Let me know if an example is required but the procedure is as simple as 
> > 1 create data too large for a cell
> > 2 apply left alignment NOT default as this will not permit indent definition
> > 3 apply 3 point indent
> > 4 apply word wrap
> > 5 redefine left align to right align
> > 6 Observe anomaly
> > 7 Revert to left align
> > 8 Observe anomaly
> 
> It gets better. If two colimns are present and the left right formatting
> exercise is performed on the right cells it works as above
> If the left cells are then formatted left/right it "wipes out" the
> formatting to the right cells and will not recognise further formatting
> endeavours to those cells.
> 
> My apologies for "chopping and changing" my comment - not sure whether the
> protocol is to keep filing new comments as my appreciation of the error's
> impact develops or append to my original comment as everything is as yet
> unaddressed.

If the cells refusing to be reformatted are selected and direct formatting is cleared then the cells can be successfully re-formatted lef/right/indent with no impact on the adjacent column's formatting

Version: 7.6.0.0.alpha0+ (X86_64) / LibreOffice Community
Build ID: 0f2581204a70038ed7ca78089a9bd96d158e02c0
CPU threads: 16; OS: Linux 5.19; UI render: default; VCL: gtk3
Locale: ro-RO (ro_RO.UTF-8); UI: en-US
Calc: threaded

Working only after changing to left, changing the value, then again moving to right. So, it seems it is a widget/UI bug.

Retested with
Version: 7.6.0.0.alpha0+ (X86_64) / LibreOffice Community
Build ID: 0f2581204a70038ed7ca78089a9bd96d158e02c0
CPU threads: 16; OS: Linux 5.19; UI render: default; VCL: gtk3
Locale: ro-RO (ro_RO.UTF-8); UI: en-US
Calc: threaded