error on inplace update, by rendering wrong value for decimal field in genereated UPDATE clause

I have a table with 4 fields at all, one of them a decimal (6,2) field. Trying inplace update of a single field in grid, ie selecting that field (any of the non-decimal ones), inputting an new value, and pressing eg downarrow, seems to create an erroneous UPDATE statement, causing the "0, should have been 1" error.
The error appears to be that the decimal field´s value is rendered without an appropriate (,2) decimal point; eg update of `type` field generates

UPDATE `ausgaben` SET `type`='kaffee' WHERE `date`='2011-12-25' AND `amount`=569 AND `type`='kleidung' AND `comment`='tanke' LIMIT 1;

where the value of amount is really 5.69 .

See issue #2608

Ok... (whatever 'rossplantilla' may be...)