in reply to Odd lexical variable behavior -- why does this happen?

Dumping the reference with Devel::Peek inside your sub count_up 
sub count_up {
        $mw->update;
        my $progress = 0;
        warn "after \$progress init($counter):\n";
        Dump($progress);
        $pb->configure(
                -from => 0,
                -to   => 20,
                -variable => \$progress,  ## store the reference.
        );

        my $cnt = 0;
        print "\$cnt=$cnt; \$progress=$progress\n";

        for (1) {
                $progress++;
                warn "\$progreess in for() loop($counter):\n";
                Dump($progress);
                $cnt++ unless ($_ % 2);
                $mw->update;
        }
        $counter++;
        $mw->update;
}

[download]

reveals 

after $progress init(0):
SV = IV(0x8e2a5c8) at 0x8de8ce8
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,IOK,pIOK)
  IV = 0
$cnt=0; $progress=0
$progreess in for() loop(0):
SV = PVMG(0x8e74828) at 0x8de8ce8
  REFCNT = 8
  FLAGS = (PADBUSY,PADMY,GMG,SMG,RMG,pIOK)
  IV = 1
  NV = 0
  PV = 0x8eb73d8 "0"\0
  CUR = 1
  LEN = 4
  MAGIC = 0x8eb67d8
    MG_VIRTUAL = &PL_vtbl_packelem
    MG_TYPE = PERL_MAGIC_tiedscalar(q)
    MG_FLAGS = 0x02
      REFCOUNTED
    MG_OBJ = 0x8eb4780
    SV = RV(0x8b5ffa0) at 0x8eb4780
      REFCNT = 1
      FLAGS = (ROK)
      RV = 0x8eb484c
      SV = PVHV(0x8d7a4c8) at 0x8eb484c
        REFCNT = 2
        FLAGS = (OBJECT,SHAREKEYS)
        IV = 7
        NV = 0
        STASH = 0x8dd4694       "Tie::Watch::Scalar"
        ARRAY = 0x8eb6790  (0:3, 1:3, 2:2)
        hash quality = 111.4%
        KEYS = 7
        FILL = 5
        MAX = 7
        RITER = -1
        EITER = 0x0
        Elt "-shadow" HASH = 0x54c7bc48
        SV = IV(0x8e2a4c4) at 0x8eb4858
          REFCNT = 1
          FLAGS = (IOK,pIOK)
          IV = 1
        Elt "-destroy" HASH = 0x467b93a1
        SV = RV(0x8b5ff94) at 0x8eb4864
          REFCNT = 1
          FLAGS = (ROK)
          RV = 0x8e7d448
          SV = PVAV(0x8ead8c4) at 0x8e7d448
            REFCNT = 1
            FLAGS = ()
            IV = 0
            NV = 0
            ARRAY = 0x8eb4560
            FILL = 1
            MAX = 1
            ARYLEN = 0x0
            FLAGS = (REAL)
after $progress init(1):
SV = IV(0x8e2a4d0) at 0x8e592f0
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,IOK,pIOK)
  IV = 0
$cnt=0; $progress=1
$progreess in for() loop(1):
SV = PVMG(0x8eb5778) at 0x8e592f0
  REFCNT = 8
  FLAGS = (PADBUSY,PADMY,GMG,SMG,RMG,pIOK)
  IV = 2
  NV = 0
  PV = 0x8eb74f0 "1"\0
  CUR = 1
  LEN = 4
  MAGIC = 0x8eb6a98
    MG_VIRTUAL = &PL_vtbl_packelem
    MG_TYPE = PERL_MAGIC_tiedscalar(q)
    MG_FLAGS = 0x02
      REFCOUNTED
    MG_OBJ = 0x8eb4a8c
    SV = RV(0x8b5ffd8) at 0x8eb4a8c
      REFCNT = 1
      FLAGS = (ROK)
      RV = 0x8eb4b58
      SV = PVHV(0x8d7a4f8) at 0x8eb4b58
        REFCNT = 2
        FLAGS = (OBJECT,SHAREKEYS)
        IV = 7
        NV = 0
        STASH = 0x8dd4694       "Tie::Watch::Scalar"
        ARRAY = 0x8eb8e88  (0:3, 1:3, 2:2)
        hash quality = 111.4%
        KEYS = 7
        FILL = 5
        MAX = 7
        RITER = -1
        EITER = 0x0
        Elt "-shadow" HASH = 0x54c7bc48
        SV = IV(0x8e2a5d8) at 0x8eb4b64
          REFCNT = 1
          FLAGS = (IOK,pIOK)
          IV = 1
        Elt "-destroy" HASH = 0x467b93a1
        SV = RV(0x8b5ffcc) at 0x8eb4b70
          REFCNT = 1
          FLAGS = (ROK)
          RV = 0x8e593a4
          SV = PVAV(0x8ead814) at 0x8e593a4
            REFCNT = 1
            FLAGS = ()
            IV = 0
            NV = 0
            ARRAY = 0x8eb68b0
            FILL = 1
            MAX = 1
            ARYLEN = 0x0
            FLAGS = (REAL)

[download]
that the Progressbar object remembers the value from the previous configured reference via Tie::Watch voodoo, and you can't reset that value by just passing another reference to configure.

How cool is that? You can't stop progress :-)

--shmem 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

In Section Seekers of Perl Wisdom