reporting services - 0-value not showing in line graph -

i have dataset contains lot of records.

employee (varchar) | month (int) | sales (money) john | jan | 15 john | jan | 6 hank | jan | 20 mike | jan | 0 hank | jan | 12 pete | jan | 0 pete | jan | 7 john | feb | 4 john | feb | 9 hank | feb | 0 pete | feb | 11 mike | feb | 15 john | mar | 0 hank | mar | 20 mike | feb | 0 pete | mar | 10 pete | mar | 12 

each name exists each month , has value (albeit 0)

i have tablix grouping , correctly shows:

     | jan | feb | mar john |  21 |  13 |  0  hank |  32 |   0 | 20 pete |   7 |  11 |  0 mike |   0 |  15 |  0 

(actually, there mike, edward, michelle, blake , on)

a line graph based on dame dataset omits values '0'. lines broken, there gaps. except first 2 have no '0' in sequence. john , pete shown jan - feb - mar , hank's line shows gaps.... if set hank on 11 in feb , pete 0 in feb, john , hank shown no gaps in lines. so, if there '0' @ end, line continues should, there 0 in middle there gaps in line there 0's. employee after (mike, blake, michelle, etc) has gaps wherever line should touch zero. toyed around emptypoints , fill gaps (e.g. red line) why john , pete shown normal line goes way end, filling 0's while others have red line (emptypoint)?

and strictly spoken, there no empty/null's, '0'. or mistaken?

why can't chart show same tablix does?

not sure what's happening report, there's nothing wrong data or getting display in chart.

data (slightly modified better align tablix):

select employee = 'john' ,month = 1, monthname = 'jan' ,sales =  15 union select employee = 'john' ,month = 1, monthname = 'jan' ,sales =  6 union select employee = 'hank' ,month = 1, monthname = 'jan' ,sales =  20 union select employee = 'mike' ,month = 1, monthname = 'jan' ,sales =  0 union select employee = 'hank' ,month = 1, monthname = 'jan' ,sales =  12 union select employee = 'pete' ,month = 1, monthname = 'jan' ,sales =  0 union select employee = 'pete' ,month = 1, monthname = 'jan' ,sales =  7 union select employee = 'john' ,month = 2, monthname = 'feb' ,sales =  4 union select employee = 'john' ,month = 2, monthname = 'feb' ,sales =  9 union select employee = 'hank' ,month = 2, monthname = 'feb' ,sales =  0 union select employee = 'pete' ,month = 2, monthname = 'feb' ,sales =  11 union select employee = 'mike' ,month = 2, monthname = 'feb' ,sales =  15 union select employee = 'john' ,month = 3, monthname = 'mar' ,sales =  0 union select employee = 'hank' ,month = 3, monthname = 'mar' ,sales =  20 union select employee = 'mike' ,month = 3, monthname = 'mar' ,sales =  0 union select employee = 'pete' ,month = 3, monthname = 'mar' ,sales =  10 union select employee = 'pete' ,month = 3, monthname = 'mar' ,sales =  12 

a basic chart, created adding fields respective areas:

only other action change label monthname.

which looks like:

all names showing points months. understand doesn't specific issue show can work intended. in case create new chart entirely, add in basic fields above , see how looks; once going can add more formatting, etc, checking still works @ each step.