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Slurs

b. 1-2

composition: Op. 28 No. 21, Prelude in B♭ major

Slur from to c1 in A

Slur from B1 to c1 in FC (→GE)

Slur from to B in FE (→EE)

..

In the main text we give the slur of FE (→EE), since the vast majority of subsequent slurs, present in a similar context, is led to the 1st quaver in the next bar in A – out of 13 slurs in b. 1-12 and 15, it is only the slurs in b. 1, 8 and 10 that end on the 6th quaver; two (in b. 6 and 9) are ambiguous. We consider all the above slurs to be inaccurate, since the differences in the range of slurs are not related to the structure of motifs, e.g. the shorter slurs in b. 1 and 8 are opposed by the longer ones in similar figures in b. 2 and 7. Moreover, in A one can see corrections – the slurs in b. 4-5 and 5-6 were being extended (in b. 3-4 probably too). Along with the crossed-out staccato dot at the beginning of b. 2, it may indicate that the concept of markings of those figures changed from  to . Consequently, the aforementioned shorter slurs would be uncorrected elements of the initial slurring.
The slur beginning from the 1st quaver is an inaccuracy of Fontana, repeated in the next three bars too.   

category imprint: Differences between sources

issues: Corrections in A , FE revisions , Omitted correction of an analogous place , Inaccuracies in FC

b. 2-4

composition: Op. 28 No. 21, Prelude in B♭ major

Slurs from 2nd quaver in A (→FEEE)

Slurs from first quaver in FC (→GE)

..

The ending of the slur from b. 2 led to b. 3 is hardly visible in A, which probably convinced Fontana that the slurs of L.H. figures were supposed to end on the last quaver in the bar, like in b. 1 (it is likely that it was only after he had seen the slurs in b. 5-6 and 6-7 that he realised that he was wrong and prolonged the slur in b. 4). In the case of beginnings of the slurs, even the correct interpretation of the slurs in b. 5-7 did not make him correct the previously written slurs or keep the notation of A in further bars (in A it is only the slurs in b. 9 and 15 that can be considered vague in this respect; the remaining ones clearly begin on the 2nd quaver). In the main text we give the notation of A (also in further bars). 

category imprint: Differences between sources

issues: Inaccuracies in FC

b. 4

composition: Op. 28 No. 21, Prelude in B♭ major

..

In FC (→GE) the slur reaches e1, which is a crotchet on the 3rd beat of the bar in these sources (filling the bar after the g1 minim), and not the top note of the last L.H. quaver.
See the next note.

category imprint: Differences between sources

issues: Errors of FC

b. 4-5

composition: Op. 28 No. 21, Prelude in B♭ major

Slur from 2nd quaver to bar 5 in A (→FEEE)

Slur from first quaver to bar 5 in FC

Slur from first to 6th quaver in GE

..

In the main text we give the slur of A (→FEEE). The slur of FC starts a quaver earlier, whereas GE also moved its ending, which made it resemble the previous slurs, thus consolidating a distorted image of articulation of these figures – see the notes in b. 1-2 and 2-4.

category imprint: Differences between sources

issues: Inaccuracies in GE , Inaccuracies in FC

b. 6-7

composition: Op. 28 No. 21, Prelude in B♭ major

..

In A the end of the L.H. slur in b. 6, which closes the line, clearly points to continuation, which is, however, absent in b. 7. In this case, it did not result in discrepancies in the remaining sources, since both FE (→EE) and FC (→GE) led the slur to the beginning of b. 7, undoubtedly in accordance with Chopin's intention.

category imprint: Graphic ambiguousness; Source & stylistic information

issues: Inaccurate slurs in A , Uncertain slur continuation