Assuming that most of the time when you are about to start a long
operation, you want to show a short text in the leftmost plain-vanilla
text pane, and immediately next to it a progress bar, a nice solution
would be not to disturb the content of the status bar, create a progress
control, initialize and advance it until operation is complete, then
return the status bar to its initial state (idle text). This way, you do
not have to add/remove panes in the status bar neither to resize or
otherwise alter the panes, because usually all panes on a status bar are
grouped rightmost, and the remaining space is used for regular text
messages.
This can be best achieved by deriving a class from CStatusBar and adding
a CProgressCtrl child in it. We can then add members to the new
CStatusBarWithProgress to hide/show and control the progress bar.
All these prepared, you can now open up your frame class’ header, and
simply change CStatusBar with our new CStatusBarWithProgress. That’s
all.