Known browser issues

Because of the nature of Fonto Editor, it depends heavily on how a browser behaves. Unfortunately, these browsers may not be perfect and they may misbehave in some circumstances. When a browser shows a bug, we at Fonto will try to file a bug so that the browser vendor may fix it, if it is not already reported. If possible, we will implement a work-around for the issue and release it with the next version of Fonto Editor.

Microsoft Edge (Legacy)

Aside from a number of performance related issues, we are aware of the following issues with version 44 of Microsoft Edge:

Starting from version 81, Microsoft Edge has switched to the same browser engine as Google Chrome. For that version onward, please refer to the list of Chrome-specific issues below.

Incorrect cursor location in tables

Edge will sometimes place the cursor in between two rows of a table. This usually "fixes" itself when you start typing, causing the cursor to jump back to a valid location.

Clicking inside a selection will not correctly place the cursor

Due to a browser bug, Edge does not notify Fonto Editor of the selection change in this case. As a result, although the cursor may appear visible, Fonto Editor will still consider the previously selected content to remain selected. To work around this issue, click twice to place the cursor at any position inside an existing selection.

Expanded tables might not expand completely

Large tables can be shown in an expanded view as of editor version 7.8.0. The table, while expanded, might not take up all available space inside its container due to a widget that's "in its way". We recommend not placing widgets at the side of a table (such as the element menu) if this causes problems for your application.

Empty paragraphs are sometimes skipped when pressing the up and down cursor keys.

This issue is not reported, but it does not occur in the insiders preview for the next version of Edge (44). This is scheduled to be released in the Windows 10 October 2018 Update.

View updates are sometimes disabled when the F12 developer tools are opened.

This issue is reported as

We see that using the Microsoft Edge DevTools Preview does not trigger this issue.

Localization does not always use the correct date format.

Combined diacritical marks are not rendered correctly.

Selection across some element boundaries does not work correctly.

This issue is reported as

Users can use the keyboard to extend the selection, but this is not rendered.

Opening popovers may cause the browser to scroll to a random place.

Squiggles are rendered much lower than in other browsers.

This issue has not been reported.

Highlights may be rendered in front of text.

This is caused by Edge missing support for the mix-blend-mode CSS property.

As a work-around, all versions of Fonto fall back to overlaying the highlights using opacity, which unfortunately causes text to be slightly colored.

The cursor is rendered too small when moving between text with different font sizes.

This issue has not been reported.

Moving the cursor again usually restores the cursor to its proper size.

Various issues related to performance.

This issue has not been reported.

This causes a number of related issues, like scrolling behaviour to work Some parts of Fonto use viewport culling to physically remove invisible parts of the view from the HTML dom. This improves scrolling performance because the browser does not have to lay-out and measure these parts. This may cause unstable scroll positions in Edge when a new part of the view being rendered. This mainly happens when Edge is also having other performance related problems. This issue manifests itself in both the content view and in the structure view.

Drawing a selection over buttons keeps tooltips open

This issue has not been reported.

The cursor may be drawn in front of certain UI elements

This includes the context menu. This is a visual bug - both the menu and cursor should still work as expected.

This issue has not been reported.

Table row widgets might be incorrectly positioned

Widgets in front of table rows may not be centred in front of a table row. This is only a visual bug, the button should work as expected.

This issue has not been reported.

The new remote document state widget is sometimes partially behind sheetframes

This issue has not been reported.

Dragging the mouse to use the new Table Cell Highlighting mode does not work.

The other ways to expand the cell selection do work, such as holding shift while using the arrow keys or clicking on a cell while holding the shift key.

This issue has not been reported.

Mozilla Firefox

We are aware of the following issues in Firefox:

Selecting text in multiple table cells does not work properly.

Firefox may incorrectly select table cells while dragging the cursor across a table to expand the selection. It will also show blue outlines when this happens. This usually causes the selection to only grow - the selection will not shrink anymore when moving the cursor back over already selected cells. To work around this, release the mouse and create a new selection, or use shift and the left / right arrow keys to shrink the selection to the desired range.

Scrolling a block-level equation while it is selected does not work properly.

This only happens when the block-level MathML equation is selected. While the equation is selected, it is nearly impossible to scroll it inside its container. Being able to scroll large block-level MathML equations has been introduced in editor version 7.8.0.

Vertical cursor movement after horizontal cursor movement may jump to an unexpected position.

This issue is reported as Fonto 7.10 contains a fix for this issue.

Right-clicking to open the context menu may unexpectedly scroll and/or move the cursor to an unexpected place.

Right clicking a sheet frame that does not currently have focus will move the cursor to the start of that sheet frame in Firefox, instead of to the location that was clicked. This may cause selection-based contextual operations to either be disabled or scrolled out of view. To work around this, left-click to place the selection before opening the context menu.

This issue has not been reported.

The XML source view and inactive selection sometimes show content before the selection as selected.

This usually happens when the selection starts (or the cursor is placed) at the end of an element, and causes the content of said element to appear selected while it is not part of the selection. The active (yellow) selection in the content view is not affected by this issue and should always accurately represent the current selection.

This issue is reported as

Sidebar tab button labels sometimes move a bit when hovered.

Firefox 77.0, 77.0.1, and newer 78.beta versions on Linux and Windows have this issue, MacOS seems to work fine in all versions.

Fully selecting a table and then trying to horizontally scroll the table will drag instead of scroll

When selecting the full table and then scrolling it horizontally doesn't scroll, but drags the selection. This issue has not been reported.

Highlighting uneditable content

Markup labels look selectable in Firefox due to highlighting when they are selected. However, when trying to copy and paste these labels they are not pasted.

Google Chrome

We are aware of the following issues in the supported versions of Google Chrome.

Browser crash when pressing page-down in extremely rare circumstances.

The cursor is sometimes rendered behind the background of an inline frame.

This issue has not been reported.

Fonto contains a work-around for this issue by making these background colors slightly transparent. Custom background colors of inline frames must also be slightly transparent to prevent this issue from appearing in your editor.

Extending the selection using shift + arrow up / down can result in both a selection and a blinking cursor being shown at the same time.

The blinking cursor represents the correct selection - the highlighted selection is harmless and should disappear after any change to the document or cursor position.

This issue has not been reported. Fonto 7.10 contains a fix for this issue.

Selecting a table row may cause a large blinking cursor to appear next to the table

The highlighted row represents the correct selection. The blinking cursor is harmless and should disappear when the selection is moved elsewhere.

Right-clicking on tables can cause the document to scroll unexpectedly on MacOS

This is caused by Chrome creating an unexpected selection when right-clicking a table. This only occurs on MacOS.

Border rendering in table cells

If a cell has solid border and there is another merged cell with a dashed or dotted border below or above this cell, the solid border will overflow in Chrome. The Chrome team is aware of the issue. Similarly, various other combinations of different styles set for overlapping borders may not always be displayed as expected in Chrome.

Whitespace visualization displays extra spaces that do not exist in the content

Starting from Chrome 88, the fontoxml-whitespace-visualization add-on may display some spaces that are not part of the actual content. Chrome version 87 and earlier, as well as Edge 88 and earlier and current versions of Firefox are not affected. The Chrome team is aware of the issue.

Fonto Editor 7.15.0 contains a fix for this issue.


Right-clicking may create unexpected selections

In Safari, right-clicking tends to select content. This interacts with Fonto in unintended ways, which may cause unexpected highlights and/or a disappearing cursor when right-clicking. Right-clicking existing selections should work as expected.

Expanded tables may not use the full width of the expanded area

This is usually the result of using an element menu on the table or a surrounding element. Removing that widget should solve the issue.

Selecting a table, table cell, inline image or similar structures may highlight additional content

This most often shows up as highlighted blank areas directly after the expected selection. The actual selection is not affected, and operations should behave as expected given the intended selection. The grey inactive selection (shown when other parts of the UI have focus) should always highlight the correct content.

Selecting a table, table cell, inline image or similar structures may show a blinking caret

This can happen when selecting a formula. The blinking cursor is just visual, the selection is placed correctly in the XML and adjusting the selection corrects it.

Right-clicking on a table cell loses focus highlight

This happens if your cursor is at the end of the text-container or if you have no text inside a table cell. If you then right-click inside the table cell, the cell loses the focus highlight.

Right-clicking certain elements could cause unexpected scrolling

This happens most frequently when right-clicking images in sheet frames that do not contain the cursor. To work around this issue, first select the image by left-clicking, then right-click to open its context menu.

Using iframes inside views can crash the editor

Safari does not behave as expected when iframes are used inside views. We highly discourage the use of iframes inside views as there are also other known issues.

Various browsers

IME: incorrect cursor position

The cursor position may end up in an unexpected location after inserting multiple characters using an IME.

Some forms of input are not detected correctly.

This includes IME input, MacOS' accents inserted by holding a key and some dead-key configurations under Linux.

Users may use the fontoxml-special-characters add-on. An editor can declare an operation to insert a special character by pressing a keybinding and using the insert-text operation. Alternatively, content containing special characters can be pasted from other applications.

If you are seeing a yellow selection on one character or no selection at all, you probably pressed the insert key. Insert is not supported at this moment due to browser limitations.

Copying and pasting content between different browsers may lose formatting.

Copying and pasting XML content between browsers may be disabled because of security concerns enforced by either the operating system or one of the browsers. This is not something Fonto Editor can address.

Unexpected word wrapping changes when moving the cursor

Placing the cursor in certain positions can cause some changes in the way lines of text are wrapped to fit the surrounding element. You may see parts of a sentence move to the next line, a blank line appearing before long words, or in rare cases long words overflowing the element's boundaries. These issues do not affect the XML content in any way, and moving the cursor away should resolve the issue.

Cursor may jump between the start and end of a line when moving the cursor

This can happen around places where the text wraps to a new line. Browsers do not offer a way to consistently place the cursor at the end of the line or the start of the next one. As both visual positions represent the same position relative to the content, this should not affect editing.

Fuzzy (menu) text.

In certain situations, certain text in Fonto might look unsharp. This is most likely due to not viewing the content at "Actual Size" but slightly zoomed in or out. Make sure your browser zoom is reset to 100% or "Actual Size" by pressing CMD/CTRL+0.

Note: Fonto Editor provides built-in document zoom options that you could configure and offer to your users if you like.

Large widgets in blockBefore / blockAfter / blockOutsideBefore / blockOutsideAfter can create unexpected whitespace in nested elements

When multiple elements are nested in a block-like family that has a large widget in one of its horizontally adjacent widget areas, browsers may move the second and further nested elements below the bottom of the widget, creating unexpected whitespace.

Fonto 7.7 contains a work-around for the issue for Chrome and Firefox. Due to browser limitations it is not possible to work around this issue for Edge and Safari.

Making a selection at the end of a document with Shift + Arrow keys might show an inaccurate selection in the XML View

Applicable in single and multiple document editors. The selection shown in the content editor corresponds with the actual one, but the one shown in the XML View might not reflect that selection.

Drag & drop requires holding down the mouse button for a short while

Sometimes, a drag requires you to hold down the mouse button for a short while before content can be moved. This is due to operating system settings, which may or may not be respected by the browser you are using. This is most often observed on MacOS.

Drag & drop does not work as expected

The drag & drop feature in Fonto Editor is dependant on the capabilities of the browser Fonto Editor runs in, the operating system running that browser, and the source application from which content is dragged. They have to work in unison for drag & drop to work. In certain scenario's, it is unfortunately possible that Fonto Editor is not allowed access to dragged content and cannot import it as a result.

SVG files without height and width

Fonto Editor determines the sizes of an SVG file according to its intrinsic dimensions while rendering. When the SVG file does not have height and width, the supported browsers report its intrinsic dimensions different from each other. That's why, if you check an SVG file without height and width in different browsers, you can observe its sizes in Safari different than Chrome and Firefox. To fix this, please set height and width to your SVG file, so they will be rendered alike in all the browsers.