fix aw_string_selection inconsistencies

[westram]

differences between motif and gtk:

• using default 'Cancel' button
  • returns NULL in motif
  • returns current inputfield-content in gtk (making it necessary to perform an extra test) fixed by [12247]

general inconsistency:

• using non-default 'Cancel'/'Abort'/'Close' is impossible fixed by [12247]; used by [12248]

Solution:

• eliminate default button (always pass from caller)
• declare one button as abort-button (return NULL if that button has been pressed, as aw_input does)
  • e.g. by prefixing it with '-' (e.g. "Ok,-Abort")done by [12244] + [12247]

It would also be nice to have a default button which gets triggered when the

• presses 'ENTER' in the input field or
• double clicks an entry in the selection box.

The default button could be marked by prefixing its name with '+'.

[westram]

• entering an empty string should
  • either be denied or
  • act like abort.

Check behavior for aw_input as well.

Bad idea: several callers of aw_input use an empty result to delete things (e.g. "SAI description" or "SAI group")

[westram]

aw_input2awar:

• unused outside WINDOW library
• gtk-version changes awar (while typing) and leaves last entered value in case of 'Abort'
• motif-version changes awar once
  • to last value when ok was pressed
  • to "" when abort was pressed
• signature differs between gtk and motif

[westram]

aw_input2awar:

• unused outside WINDOW library

removed from motif [12250]; hidden in gtk/WINDOW [12251]

• gtk-version changes awar (while typing) and leaves last entered value in case of 'Abort'

• still changes awar while typing (might be problematic in some cases; fix then)
• restores previous value since [12249]

[westram]

Replying to westram:

It would also be nice to have a default button which gets triggered when the

• presses 'ENTER' in the input field or
• double clicks an entry in the selection box.

The default button could be marked by prefixing its name with '+'.

moved to #540

[westram]

Milestone powerusability deleted