Support
The fastest way to get help is to open an issue on GitHub. Bug reports, feature requests, and questions all go to the same place, and you'll get a faster answer there than by email.
Before you file
A few things resolve most reports on their own.
The grid doesn't line up with my columns
Check the Bootstrap version in the Tooltips tab. Container widths and gutters differ between Bootstrap 3, 4, and 5, so the overlay follows the detected version. If detection guessed wrong — which happens on pages that load Bootstrap's CSS without its JavaScript — set the version manually and the overlay will redraw.
Also confirm which container the section uses. A .container-fluid spans the full viewport while a .container is capped per breakpoint; switch Container Type in the Grid tab to match.
Why is there no breakpoint on the toolbar icon?
The badge appears on pages that use Bootstrap, and stays off everywhere else — a breakpoint label on a page with no Bootstrap grid would be meaningless, and badging every tab in the browser is noise.
If a page does use Bootstrap and the badge is still missing, check the version readout in the Tooltips tab. Detection looks at the page's JavaScript globals, its --bs-* CSS variables, the grid itself, and finally its markup — so a page has to be hiding Bootstrap quite well to escape all four. Bootstrap loaded very late by a single-page app can take a few seconds to register.
Nothing happens on this page
The extension can't run on browser-internal pages — chrome://, about:, the Chrome Web Store, and Firefox's add-on gallery are all off limits to every extension, by browser policy rather than by choice. It also won't run on tabs that were already open when you installed it; reload those once.
Does the grid follow me to other sites?
No, on two counts. Visibility is per tab, so switching it on for the page you're working on leaves every other tab untouched and new tabs open clean. And the overlay only draws on pages that actually use Bootstrap — navigate the same tab to a site with no Bootstrap and it disappears, then comes back by itself when you return, without you having to toggle it again.
Before 1.3.0 visibility was remembered globally and followed you everywhere. Before 1.6.0 it stayed on within a tab regardless of what the next page was. Update if you're seeing either.
Show Grid is greyed out
No Bootstrap was detected on that page, so there's no grid to overlay. If you know Bootstrap is there — a heavily customised build, say — set the version manually in the Tooltips tab instead of leaving it on auto-detect, and the overlay will draw regardless.
How do custom breakpoints work?
A breakpoint is a name and the width it starts at — the same shape as Bootstrap's $grid-breakpoints. Each one runs until the next begins and the last runs to infinity, so the ranges shown beside each row are worked out for you rather than typed. That is deliberate: entering both ends lets them disagree, which is how you get gaps and overlapping breakpoints.
The editor opens pre-filled with Bootstrap's defaults, so you can change one value rather than retyping all six. Rows re-sort themselves when you finish editing a width, and anything that would stop a set working — a missing name, two breakpoints starting at the same width — is flagged before you can save.
Can I share a set of breakpoints?
Yes. Open Import & export under Custom Breakpoints. The box holds the current set as JSON: copy it, or download it as a file to commit alongside a project. To load one, paste it in and press Apply, or use Load from file.
Import is deliberately forgiving about shape. It accepts a file exported from GridLens, a bare array of {"name": "...", "minWidth": ...} entries, or the plain {"sm": 576, "md": 768} map you can lift straight out of a project's Sass.
Switching container type doesn't seem to change anything
Three things to check. Below 576px wide, .container is full-width anyway, so it and .container-fluid are genuinely identical — widen the window and the difference appears. The overlay also has to be switched on to see any change to it. And if you loaded the extension from source, reload it at chrome://extensions after updating; the version shown at the bottom of the popup tells you which build is actually running.
Which components can GridLens open?
Modals, offcanvas panels, toasts, dropdowns, tabs and pills, collapse sections and accordions, carousels, and popovers — everything Bootstrap drives with JavaScript. They are grouped by kind in the Components tab, and listed whether or not anything on the page opens them.
Opening a modal or offcanvas closes whichever one was already open first, since only one can own the screen. The rest — toasts, dropdowns, tabs, accordions — are left alone, because they legitimately coexist.
Components that only exist in newer Bootstrap versions simply do not appear on older pages: no offcanvas on Bootstrap 4, no toast on Bootstrap 3.
Tooltips or modals don't respond
Confirm the page actually uses Bootstrap's JavaScript, not just its stylesheet. The Tooltips tab reports how Bootstrap was detected — hover the version readout. If it says the stylesheet or the markup rather than the JavaScript, the page has no Bootstrap JS for the extension to drive, so the grid overlay works but tooltips fall back to a simple renderer and modals may not open.
Reporting a bug
Include these and the fix will be much faster:
- Browser and version, and your operating system
- The Bootstrap version the page uses, and what the extension reported
- A URL that reproduces it, or the relevant markup — a CodePen is ideal
- What you expected versus what happened
- Anything logged in the browser console
Privacy and data
GridLens collects nothing, sends nothing, and has no server — so there's no account, no stored history, and nothing for anyone to delete on your behalf. Removing the extension removes everything it saved. See the privacy policy for the specifics.
Source code
GridLens is MIT licensed and the full source is on GitHub. Nothing is minified or bundled, so what you read in the repository is exactly what runs in your browser.