--- title: "Boss’nX schema canvas: troubleshooting and frequently asked questions" description: "W and H missing, locked ratio, grid step grayed out, background image invisible or rejected: answers about the canvas of the Boss’nX schema editor." canonical: https://wiki.can-nx.com/en/guides/boss-schema-canvas-help/ language: en product: Boss’nX audience: - administrateur - installateur context: "Boss’nX, schema editor on a computer: dimensions, grid, zoom and layer backgrounds" --- # Boss’nX schema canvas: troubleshooting and frequently asked questions Context: Boss’nX, schema editor on a computer: dimensions, grid, zoom and layer backgrounds W and H fields missing, height changing on its own, grid step grayed out, background image invisible or rejected, unsaved changes: here are the answers to common questions about the canvas of the Boss’nX schema editor, on a computer, for administrators and installers. The full procedures are in [dimensions and grid](https://wiki.can-nx.com/en/guides/boss-schema-canvas/), [navigation and history](https://wiki.can-nx.com/en/guides/boss-schema-canvas-navigation/) and [backgrounds](https://wiki.can-nx.com/en/guides/boss-schema-background/). ## Where are the W and H fields? Open **Schemas** in the header bar or in the **Menu**, then **Actions → Edit schema** on the row of the right schema. Wait for it to load, then choose **Custom** in the list of formats of the bottom bar: the W and H fields appear for this format. If **Edit schema** is missing, check [the role capabilities](https://wiki.can-nx.com/en/guides/boss-role-capabilities/). If the commands are still missing while you are in the right schema, contact support. ## How do I make the drawing bigger on screen without changing its size? Use the zoom magnifiers of the bottom bar; **Fit to screen** gives you an overall view again. Choosing a format or changing W and H changes the dimensions of the drawing itself: you do not need this just to zoom. The view commands are described in [navigation in the editor](https://wiki.can-nx.com/en/guides/boss-schema-canvas-navigation/). ## Why does the height change when I enter the width? The ratio is locked. Look at the padlock between W and H: with **Ratio locked**, the other dimension adapts. To enter two independent values, click it to get **Ratio unlocked**, then fill in W and H. Read both values again, particularly after importing an image or changing layers. ## Why is my width of 5000 not kept? The custom W and H fields are limited to **100 to 4000**. After Enter or leaving the field, read the value retained. Do not try to get around this limit through another field: if your drawing needs more, describe it to support. ## Why did Custom change the canvas size? **Custom** can take the dimensions of the background image when they are available; otherwise it starts from **1920 × 1080**. Read W and H again, unlock the ratio if you want independent values, then enter the dimensions you want. See [setting the format](https://wiki.can-nx.com/en/guides/boss-schema-canvas/). ## Why do elements seem moved after resizing? Resizing can adapt the relative positions of the elements. Check that you are on the right layer, read the width and height shown, then use **Fit to screen** to examine the drawing. To return to the previous available resize, click **Undo (Ctrl+Z)** and check the result before saving. If the expected layout cannot be found, contact support with the dimensions before and after and the action performed. ## Why is the Grid step button grayed out? The grid is turned off. Turn on the neighboring button, tooltip **Grid & snap — Alt to place freely**: it controls the grid and snapping together. The **Grid step** button becomes available when this grid is on. ## Does the background Grid pattern set the placement of elements? No. The **Grid** pattern of **Canvas background** decorates the layer. The placement aid is set with the **Grid & snap — Alt to place freely** button and the **Grid step**, as described in [the grid procedure](https://wiki.can-nx.com/en/guides/boss-schema-canvas/). ## Why is the grid step the same on several layers? The grid and its step are schema settings. The background color and pattern, on the other hand, are chosen per layer. The background picker therefore has no grid step of its own for a layer. ## Why is my background image invisible? Its opacity may be at **0%**. Check the percentage next to the image commands, before the zoom percentage. **0%** keeps the image while hiding it visually: if an image is attached to the background, increase its opacity and observe the result. If the image is still missing, check the layer and the imported file, then contact support. ## Why does the Dots pattern not show on my image? A background image takes the place of the pattern, even when its opacity is 0%. To show only the color and the **Dots** pattern, remove the image with **Remove background image**, then check the result before saving. Keep your file if you want to reimport it later. [The backgrounds guide](https://wiki.can-nx.com/en/guides/boss-schema-background/) details the consequences of removal. ## Why did Reset to white not remove the image? **Reset to white** sets the color back to white and removes the pattern; it keeps the image and its opacity. To remove the image, use the trash can next to the import, tooltip **Remove background image**, then review its confirmation. ## Why is the background image import rejected? The message shown gives the cause and the action to take: | Message | Action | | --- | --- | | **Please select a valid image file.** | Check that the chosen file is really an image and that it opens normally on your computer, then run **Import a background image** again with this file. Renaming the extension does not fix the file format. | | **The image is too large (max. ~3 MB).** | Prepare a lighter version of the image, for example by reducing its dimensions or exporting it with suitable compression, then import again. Check the rendering before saving. | If the same message persists, contact support with the file type and size, the message and the attempts already made. ## Image imported successfully: is the image saved? Not yet. **Image imported successfully.** refers to the import into the editor. Check that the right image is visible in the right layer and that **Schema name** is filled in, then click **Save** and confirm, as described in [saving a schema](https://wiki.can-nx.com/en/guides/boss-schema-editor-save/). Wait for the result, then reopen the schema and review the layer. If the expected image does not appear despite these checks, contact support. ## Why does Undo not restore my name, my grid step or my opacity? The drawing history does not cover every field. Set the desired value again yourself in the name field, the **Grid step** button or the opacity slider, as needed, then check before saving. Do not rely on an automatic restoration after reopening: for an unknown value or an uncertain recovery, contact support. ## Why do I still see Unsaved changes after a save? Some changes are still pending. Choose **Stay** to keep them, review the layer summary and any warnings, then save the changes you want. Do not use **Leave without saving** to check a save: this choice discards what is still pending. If the prompt persists after this check, contact support. ## Contact support If the problem persists after you have checked the layer, the settings and the save, write to support@can-nx.com with: Boss’nX, the schema and the layer, the expected result and the observed result, the exact message, the dimensions before and after for a resize, the file type and size for an image, and the steps already tried. A screenshot without sensitive data can help. Do not send any password or access key. Describe what you observe, for example an element that is no longer visible, without concluding that data was lost.