Can't edit materials anymore

I did something and now none of the materials in my project can be edited anymore. All I can change in the material inspector is the shader, below that there's just an empty grey area. I have the problem both if I view the material itself in the inspector and if I view a gameobject with that material attached (which brings up a small popup at the bottom of the inspector).

The problem persists for every shader and every material, even the ones in the Standard Assets package. Materials created before the problem do keep the settings I gave them (textures, colors etc.), I just can't edit them anymore. The problem isn't restricted to one scene but to the project: if I switch scenes it persists, but if I switch to a different (older or newer, doesn't matter) project I can suddenly edit materials. This doesn't provide me with a workaround though, as when I import a material from a different project (after first importing the texture assets) it sets its texture settings to the default texture (other settings, like shader, color and shininess, remain though).

I didn't immediately notice the problem, but this is some stuff I did that might have caused it:

I create a material at runtime using this code:

Custom.playerColors[i] = new Material("Shader \"Player Color " + i + "\" {SubShader{Pass{Color(" + playerColors[i].r + " , " + playerColors[i].g + " , " + playerColors[i].b + " , " + playerColors[i].a + ")}}}");

I imported some (projector) shaders from a different project (where materials do work) and I wrote a new one, which also uses the projector matrix and has a fragment program embedded in it (incidentally, it doesn't work yet). Here's the code:

 <blockquote>
   <p>Shader "Projector/Fog of War" {  
 
   Properties {   _Transparency
   ("Transparency", Float) = 0.5  
 
        _FogTex ("Cookie", 2D) = "" { TexGen ObjectLinear }
        _FalloffTex ("FallOff", 2D) = "" { TexGen ObjectLinear }   }  
 
   Subshader {
        Pass {
           ZWrite off
           Fog { Color (1, 1, 1) }       Color (1 , 1 , 1 , [_Transparency])
           ColorMask RGB         Offset -1, -1
         Blend DstColor OneMinusSrcAlpha</p>
 
 </p><pre><code>    CGPROGRAM // Upgrade NOTE: excluded shader from OpenGL ES 2.0
 </code></pre>
   
   <p>because it does not contain a surface
   program or both vertex and fragment
   programs.</p>
   
   <h1>pragma exclude_renderers gles</h1>
 
 <pre><code>    #pragma fragment DrawTexture
 
     sampler2D _FogTex;
     float4x4 _Projector;      float _Transparency;
 
     struct outputWithVariable         {
     float4 color : COLOR;
     float partOfTransp;       };
 
     outputWithVariable DrawTexture (float4 color : COLOR, float4
 </code></pre>
   
   <p>textureCoord : TEXCOORD0)
           {
           float3 projectedTextureCoord = mul (_Projector, textureCoord).xyz;
           projectedTextureCoord.z = - projectedTextureCoord.z;
             float4 fogCoordinate = tex2Dproj (_FogTex,
   projectedTextureCoord);
           fogCoordinate[3] = 1 - fogCoordinate[3];
           outputWithVariable output;
             output.color = 2.0 * fogCoordinate * _Transparency *
   color;  
 
           return output;
           }</p>
 
 </p><pre><code>    ENDCG
 </code></pre>
   
   <p>}   } }</p>
 </blockquote>

I deleted the line of code that creates a new material and all the materials that were created after the problem, plus all the shaders I imported or created. After that I restarted my project, but the problem is still there.

Does anyone know or have an idea about what's going on? And more importantly, how I can fix this? Any help would be greatly appreciated. Thanks in advance!