(In reply to comment #3)
> There's code to address this bug in the following patch, which is due to go
> live by mediawiki.org on 13 September 2013:
> 
> https://gerrit.wikimedia.org/r/#/c/82858/
> 
> Please let us know whether it fixes the bug!

The patch doesn't fix the bug. The behaviour has changed, however, and on first look it appears to be for the worse.

System environment:
Win 7 X64 SP1
Google Chrome 29.0.1547.66 m

Input and expected output:
Same as in comment 0

Test at hindi wikipedia:
Test url:
https://hi.wikipedia.org/wiki/%E0%A4%B8%E0%A4%A6%E0%A4%B8%E0%A5%8D%E0%A4%AF:Siddhartha_Ghai/sandbox?veaction=edit

What actually happens: (is too weird to be explained without prose)
1. After inputting 2 newlines, as soon as a is pressed, VE shows input of अ but one line above the current line, i.e caret automatically moves from line 3 to line 2.
2. Further inputting gar[SPACE] makes bug 53706 to show up, ie we have अगर[SPACE] in the second line with the space and newline selected, and the formatting dropdown having blanked.
3. Then inputting m makes म् appear, but its in the next line, i.e line three.
4. The caret has also moved back to line three ahead of it.
5. Then, when the final a is input, the अगर[SPACE] in line two changes to अग with the र[SPACE] having moved to the beginning of line three followed by म . The text in line three is irremovable.

Test at Mediawiki.org:
Test url:
https://www.mediawiki.org/wiki/User:Siddhartha_Ghai?veaction=edit

Firstly the page is blanked and the formatting reset to paragraph. The input described in Comment 0 is then done.

What actually happens:
Step 1-5 same as hindi wikipedia.
Following this, after a (noticeable) fraction of a second, the text र[SPACE]म appears in the first line and the newline between lines 1 and 2 is selected.
Caret movement is weird. When caret is at the end of the text (i.e end of third line), pressing a left arrow key takes it straight to the beginning of the second line. A right arrow keypress takes the caret back to end of third line. This effectively means that the text in lines two and three is non-navigable ( bug 53711 ). Pressing a backspace at the end of the third line removes the entire second line text, taking the caret to the second line. The first line is both navigable and removable. The third line text however, is irremovable.