There are many such problems. These are described below.

Unsupported or Partially-Supported Properties

Netscape Navigator 4

Does not support the properties background-position and background-attachment

Internet Explorer 4

Only supports the background-attachment property when applied to the BODY element.

Generic Problem: Incorrect Starting Position For Background Tiling

Platforms Demonstrating Problem

Netscape Navigator 4 (all platforms); Internet Explorer 4

Description of Problem

CSS states that background images should commence tiling at the upper corner of the elemetn content, excluding any padding space. However, both Navigator 4 and Internet Explorer 4 use the upper left-hand corner defined by any added left or top padding space as the starting location.

Workaround

There is no workaround -- designers must simply be aware of the difference between the background positioning specified by teh CSS specifications and the actual current implementations.

Background Color Does Not Fill Entire Background Region

Platforms Demonstrating Problem

Netscape Navigator 4 (all platforms)

Description of Problem

A background color applied to a block element, such as a paragraph or DIV, does not color the entire background region -- instead, it only highlights the text. An illustration is found in the example page ex-background1.html

Possible Workaround(s)

Use a background image -- the image will correctly fill the background region of the block element. A second example illustrating this usage is found in ex-background3.html

Background Image Causes Line Break for Inline Elements

Platforms Demonstrating Problem

Netscape Navigator 4 (all platforms)

Description of Problem

If a background image is applied to an inline element, such as an EM, then the element is formatted as a block element, with the text flow breaking both before and after the element. An example is found in the test page ex-background2.html

Possible Workaround(s)

There is no workaround -- for accurate text layout, you must avoid using CSS rules to place background images behind inline elements. block element.

Background Images Cause Unpredictable CSS Errors

Platforms Demonstrating Problem

Netscape Navigator 4 (all platforms)

Description of Problem

If a background image is applied to a block element, this will sometimes cause CSS rules to be improperly applied to all subsequent elements. This is illustrated in example ex-background2.html, where the second "yellow" paragraph has an background image -- note how this image has erroneously changed the font in this paragraph, and subsequent to this paragraph, to a normal font, instead of italic. If the string CLASS="imgg" is removed from this paragraph, then the proper italic formatting magically returns.

Possible Workaround(s)

There is no workaround -- for accurate handling of CSS rules, you must avoid using CSS to place background images behind elements.