I think this was done by design, but it's definitely an interface problem - a 
"Defect".

When you have Writer show tabs and spaces, it STILL hides the spaces in the end 
of a soft wrapped line. Even if there are, say, 20 spaces before the next word.

Some would argue that the spaces are "logcially" (?) hidden becuase the soft 
line wrapping must ignore them. But who said they're supposed to be ignored? I 
didn't. Instead I specifically chose to show hidden spaces, and they're still 
hidden. This results in fustrating and unpredictable behavior of the Backspace 
key. When you try to delete some words and the cursor comes to a soft wrapped 
line with more than one (hidden) space "in it" the cursor simply doesn't "react" 
when you press delete. This is becuase a hidden space is deleted, but the user 
as NO way of knowing since _nothing_ happens when she/he press Backspace. Even 
when she has specifically turned on Show Hidden Spaces! Clearly an interface 
bug. "Hidden" is the wrong word for this function - it should be "show relevant 
spaces" or "Show most of the hidden spaces".

The "correct" solution though is either to actually show these hidden spaces 
when the user chooses Show Hidden Spaces. This can be done by either making the 
spaces at the end of a line count as an extension of the last word before the 
soft wrap, then that word will be wrapped if there are "too many" spaces (and 
the user will know becuase she can see the spaces and see the word being 
wrapped). Or you can keep ignoring trailing spaces before a soft wrap and simply 
show the hidden spaces at the end of the line (even when they go beyond the 
page/border) or show as many spaces as there is room for and then a number 
showing how many hidden spaces there are like this "···(23)"[softwrap] then if 
the user presses backspare in those spaces 23 will decrease to 22.

Of course there should be a function to toggle/turn on/off "Ignore Spaces when 
wrapping text" too.

Cheers
-- David