Untracked or modified files clutter Git status and can be hidden locally or for everyone with ignore rules and git update-index flags.

Custom right-click menus can be built with HTML in Firefox 8+ instead of relying on browser defaults.

Rails 3 lets applications define custom configuration elements directly, avoiding extra gems or plugins for miscellaneous settings.

Separate gemsets let each Ruby application use its own installed gems. rvm use 1.8.7-p323@makandra_project_xy --create creates and switches to a new gemset.

Bulk test runs can fail with execution expired (Timeout::Error) when Selenium and WebMock interact; upgrading WebMock to 1.7+ resolves the timeout issue.

Classic XLS worksheets stop at 65,535 rows; the Spreadsheet gem writes only XLS, so larger exports need split sheets, extra columns, or XLSX output.

Find records near a latitude/longitude pair by calculating distances in SQL or using acts_as_geocodable for radius-based queries.

Require group in Ubuntu’s default Apache setup fails silently without the group authentication module. Installing libapache2-mod-auth-sys-group enables group-based access control.

Set the Rails environment explicitly when running server-side scripts to avoid using the wrong database or configuration. Rails 2 uses script/runner; Rails 3 uses rails runner.

Language-specific styling can switch background images per locale by using the HTML lang attribute in views and matching selectors in stylesheets.

Thunderbird mailing lists group contacts for easier recipient selection and broadcast email to every member from one address-book entry.

Test database setup can drift from development when schema dumps omit SQL-specific details; choose the right Rake task to keep structure, charset, and collation aligned.

tig can filter commits by path, helping find which changes touched a file, folder, or wildcard pattern without scanning every revision.

Check whether an object can perform a state transition before calling it. can_transition_ab? only verifies that a matching transition exists; validations may still block it.

Browsers may prompt to save passwords on login forms; setting autocomplete="off" on the form suppresses that prompt.

Very large forms can become unresponsive on iPad, with touch controls taking seconds to react. Showing only a limited set of inputs at once avoids the slowdown.

ActiveSupport::Memoizable can return wrong results when a memoized method is called with arguments, because true may trigger recomputation instead of being passed through.

jQuery 1.7 introduces on and off for event handling, deprecates bind, delegate, and live, and improves delegated event performance.

Downloading a remote file in Ruby can be done with open-uri; HTTP Basic Authentication credentials work when the source is protected.

Haml can render multi-line Ruby code with the :ruby filter when puts sends generated output into the template response.

Show me the page can fail to launch a browser window when launchy is outdated; upgrading to a newer version resolves the error.

Fresh Rails 3.1 apps can fail on boot when ExecJS cannot locate a JavaScript runtime, and adding a runtime gem to the Gemfile removes the error.

Persistent sign-in via remember_token keeps users logged in across browser restarts, while logout invalidates every matching session immediately by rotating the token.