diff --git a/src/servers/app/FontCacheEntry.cpp b/src/servers/app/FontCacheEntry.cpp
index b06d550876..a22a90a01e 100644
--- a/src/servers/app/FontCacheEntry.cpp
+++ b/src/servers/app/FontCacheEntry.cpp
@@ -187,6 +187,74 @@ FontCacheEntry::HasGlyphs(const char* utf8String, ssize_t length) const
 }
 
 
+inline bool
+render_as_space(uint32 glyphCode)
+{
+	// whitespace: render as space
+	// as per Unicode PropList.txt: White_Space
+	return (glyphCode >= 0x0009 && glyphCode <= 0x000d)
+			// control characters
+		|| (glyphCode == 0x0085)
+			// another control
+		|| (glyphCode == 0x00a0)
+			// no-break space
+		|| (glyphCode == 0x1680)
+			// ogham space mark
+		|| (glyphCode == 0x180e)
+			// mongolian vowel separator
+		|| (glyphCode >= 0x2000 && glyphCode <= 0x200a)
+			// en quand, hair space
+		|| (glyphCode >= 0x2028 && glyphCode <= 0x2029)
+			// line and paragraph separators
+		|| (glyphCode == 0x202f)
+			// narrow no-break space
+		|| (glyphCode == 0x205f)
+			// medium math space
+		|| (glyphCode == 0x3000)
+			// ideographic space
+		;
+}
+
+
+inline bool
+render_as_zero_width(uint32 glyphCode)
+{
+	// ignorable chars: render as invisible
+	// as per Unicode DerivedCoreProperties.txt: Default_Ignorable_Code_Point
+	return (glyphCode == 0x00ad)
+			// soft hyphen
+		|| (glyphCode == 0x034f)
+			// combining grapheme joiner
+		|| (glyphCode >= 0x115f && glyphCode <= 0x1160)
+			// hangul fillers
+		|| (glyphCode >= 0x17b4 && glyphCode <= 0x17b5)
+			// ignorable khmer vowels
+		|| (glyphCode >= 0x180b && glyphCode <= 0x180d)
+			// variation selectors
+		|| (glyphCode >= 0x200b && glyphCode <= 0x200f)
+			// zero width space, cursive joiners, ltr marks
+		|| (glyphCode >= 0x202a && glyphCode <= 0x202e)
+			// left to right embed, override
+		|| (glyphCode >= 0x2060 && glyphCode <= 0x206f)
+			// word joiner, invisible math operators, reserved
+		|| (glyphCode == 0x3164)
+			// hangul filler
+		|| (glyphCode >= 0xfe00 && glyphCode <= 0xfe0f)
+			// variation selectors
+		|| (glyphCode == 0xfeff)
+			// zero width no-break space
+		|| (glyphCode == 0xffa0)
+			// halfwidth hangul filler
+		|| (glyphCode >= 0xfff0 && glyphCode <= 0xfff8)
+			// reserved
+		|| (glyphCode >= 0x1d173 && glyphCode <= 0x1d17a)
+			// musical symbols
+		|| (glyphCode >= 0xe0000 && glyphCode <= 0xe01ef)
+			// variation selectors, tag space, reserved
+		;
+}
+
+
 const GlyphCache*
 FontCacheEntry::Glyph(uint32 glyphCode, FontCacheEntry* fallbackEntry)
 {
@@ -212,7 +280,24 @@ FontCacheEntry::Glyph(uint32 glyphCode, FontCacheEntry* fallbackEntry)
 		glyphIndex = engine->GlyphIndexForGlyphCode(glyphCode);
 	}
 
-	if (glyphIndex != 0 && engine->PrepareGlyph(glyphIndex)) {
+	if (glyphIndex == 0) {
+		if (render_as_zero_width(glyphCode)) {
+			// cache and return a zero width glyph
+			return fGlyphCache->CacheGlyph(glyphCode, 0, glyph_data_invalid,
+				agg::rect_i(0, 0, -1, -1), 0, 0, 0, 0);
+		}
+
+		// reset to our engine
+		engine = &fEngine;
+		if (render_as_space(glyphCode)) {
+			// get the normal space glyph
+			glyphIndex = engine->GlyphIndexForGlyphCode(0x20 /* space */);
+		} else {
+			// render the "missing glyph box" (by simply keeping glyphIndex 0)
+		}
+	}
+
+	if (engine->PrepareGlyph(glyphIndex)) {
 		glyph = fGlyphCache->CacheGlyph(glyphCode,
 			engine->DataSize(), engine->DataType(), engine->Bounds(),
 			engine->AdvanceX(), engine->AdvanceY(),
@@ -220,8 +305,8 @@ FontCacheEntry::Glyph(uint32 glyphCode, FontCacheEntry* fallbackEntry)
 
 		if (glyph != NULL)
 			engine->WriteGlyphTo(glyph->data);
-
 	}
+
 	return glyph;
 }