A placeholder in SSRS removes all leading whitespace from the content if HTML formatting is enabled for the placeholder. This is correct and valid for some whitespace characters, but others, such as U+00A0 (non-breaking space) should be preseved.
Note that this is NOT simply the normal HTML rendering behavior of collapsing reduntant whitespace - the placeholder control is actively removing leading whitespace, including whitespace characters like U+00A0 (NBSP) that really should be preserved.
There are additional oddities when certain Unicode whitespace characters are added to the start of the line:
adding a leading U+200C (zero-width non-joiner):
•The winforms Report Viewer renders the report perfectly
•The webforms Report Viewer renders the ZWNJ as a vertical bar | character
•Export to Word looks perfect
•Export to Excel looks perfect
•Export to PDF has spacing issues all over the page (it's a mess)
•Export to MHTML renders the ZWNJ as a vertical bar | character.
Using U+2060 (Word Joiner) is fun too:
•The winforms Report Viewer renders WJ as a small box
•The webforms Report Viewer renders the report perfectly.
•Export to Word shows the WJ as a small box
•Export to Excel shows the WJ as a small box
•Export to PDF shows the WJ as a small box, but the spacing issues are resolved
•Export to MHTML looks perfect.