Created attachment 152455 [details]
Spreadsheet showing the issue

Steps to reproduce

(1) Create new spreadsheet in libre office with the following data
	X	Y
Sunday	12	1
Monday	3	5
Tuesday	2	7
Wednesday	1	1
Thursday	6	8
Friday	10	4
Saturday	7	3

(2) Highlight the data
(3) Insert, Chart
(4) Chart Type: XY Scatter, points only, click next
(5) Data Range: $Sheet1.$A$1:$C$8
    Data series in rows, First row as label, First column as label
    click next

What expect to see:

Data Series: Sunday

Data Ranges: 
Name: $Sheet1.$A$2 
X-Values: $Sheet1.$B$2
Y-Values: $Sheet1.$C$2

What I do see:

Data Series: Sunday

Data Ranges: 
Name: $Sheet1.$A$2 
X-Values: <blank>
Y-Values: $Sheet1.$B$2:$C$2

See attached spreadsheet for an example

Thanks!