The minimal currpage is 1 and not 0 so update the check

Bug was introduced in 6c01cdd3

We are manipulating window and not screen so this is more comprehensive

It's because all strings are char[256] and not on the heap. And more,
the reallocation was a broken thing because the pointer was not
correctly updated (need return char* or parameter change).

Fix crash when saving and was introduced in d0dbd3e2