Issue 126726

Created attachment 85198 [details]
test file for Writer

Whether in Writer, Calc, or Impress, it is not possible to place cursor before any New Tai Lue vowel (U+19B0..U+19C0) or tone letter (U+19C8..U+19C9) via arrow keys or mouse clicks.  The cursor will only fall after the last consecutive vowel/tone or before the char *preceding* the sequence.  Furthermore, when the cursor is before the preceding char, pressing <Del> will delete *both that char & all following vowel/tone letters*.  The only workaround is to use <Alt> + arrow keys to go between the chars, but this is not even possible in Calc.  This means some shared module of AOO fails to implement the correct character properties of New Tai Lue vowels & tones, thinking they are combining chars.  According to Unicode 8.0, released on 2015-06-17, all these are assigned a general category of 'Lo' (Letter, other) & not 'Mc' (Mark, combining).  See http://unicode.org/versions/Unicode8.0.0/ Sections A, F, & M for the latest encoding model of the New Tai Lue script.  See also http://www.unicode.org/Public/8.0.0/ucd/UnicodeData.txt for the actual character properties in the UCD.

This problem is attested in the following builds & OS:
- AOO 4.1.2 on 32-bit English Windows Vista Business SP2
- AOO 4.1.2 on 32-bit English Windows 7 Professional SP1
- AOO 4.1.2 in VirtualBox (32-bit English Windows XP Professional SP3) on 32-bit English Windows Vista Business SP2

(NB: Windows 7 has bugs in its own New Tai Lue renderer that combine with the above cursor placement defect in AOO, making it difficult to see the defect in isolation.  It would be best to conduct the following on other OS first before getting to Windows 7.)

Steps to reproduce bug:
1. download & install Nokyung font from https://github.com/silnrsi/font-nokyung/releases/download/v1.3/silnrsi-font-nokyung-13.zip
2. unzip attached zip archive
3. open test-cursor.odt
4. on line 1, move cursor between chars 2-9 via arrow keys or mouse click *
5. on line 3, move cursor between chars 1-4 via arrow keys or mouse click *
6. on line 4, move cursor between chars 1-4 via arrow keys or mouse click *
7. on line 7, move cursor between chars 2 & 3 via arrow keys or mouse click *
8. on line 8, move cursor between chars 2 & 3 via arrow keys or mouse click *
9. on last line, move cursor between chars 3 & 4 via arrow keys or mouse click *
  * expected result for steps 4-9: cursor placed between chars in concern
  * actual result: cursor CANNOT be placed between those chars -- BUG!!!
10. repeat steps 4-9 by using <Alt> + arrow keys: cursor placed between chars
11. on line 1, place cursor before char 2 & press <Del> **
12. on line 3, place cursor before char 1 & press <Del> **
13. on line 4, place cursor before char 1 & press <Del> **
14. on line 7, place cursor before char 2 & press <Del> **
15. on line 8, place cursor before char 2 & press <Del> **
16. on last line, place cursor before char 3 & press <Del> **
  ** expected result for steps 11-16: char after cursor deleted
  ** actual result: char after cursor + *all consecutive vowels & tones* deleted -- BUG!!!
17. repeat steps 3-16 with test-cursor.odp: same results
18. repeat steps 3-16 with test-cursor.ods, equating line no. to row no.:
    - same results save step 10, which only makes column wider/narrower;
    - cursor still cannot be placed between chars in concern

Pls. implement the aforementioned chars as full chars, not combining chars, & fix this defect ASAP.  Thanks!