Total beginner on this - used quark with quark exclusive plugin to do dynamic text

1 trying to understand placeholders and text placeholders - have dragged xml content from xml structure pane onto text box - it seems to duplicate the data entry in the xml structure - is this correct

2 Also have problems with putting individual text placeholder within a text b0x - i want to be able to use static text alongside dynamic xml driven text - i am using the tag window method whereby i highlight the box to be a parent element - then i select a child elemnt by slect add tag - this put an empty placeholder as signified by a colured [] but i can't seem to preview it

3 does indesign offer text purging whereby if i have a null value in the xml file the text will reflow up a line