In the SSRS report, I've a tablix which has a single row and a single column (single cell). That row has a single rectangle that contains other rectangles containing other elements. The visiblity expression is set at the tablix level (both tablix visibility and row visibility), but not at the contained rectangles etc. The tablix has a visibility expression set as:
=Fields!ShipmentType.Value<>"Sales
The tablix row also has its row visibility set as:
=IsNothing(Fields!Calc_ShipToAddress.Value)
I've checked the values of these fields and per the values the tablix must be hidden which it is, however, it is still taking whitespace on the PDF.
There are three other tablixes; all three have just the tablix visiblity set, but not the row visibility. Interestingly, these tablixes don't take the whitespace when hidden.
I've searched online various solutions including various posts on SO too, but none has worked for me so far. I've even set the visibility of the column for that tablix, but still it takes the whitespace.
I'm putting this as an answer for any future searches in the hope that it might help someone with a similar situation.
In my case, the reason for the top tablix to be always visible as white space (although all the text in it was hidden) was the height of the top tablix. That tablix was overlapping the next tablix by a small notch and hence was visible as a white space on the report. I zoomed to 400% for something else and accidentally found this overlap.
Once I fixed tablix's height, the report functioned as expected and the tablix was hidden completely (no white space).